Grade 3 Mental Grade 3 Mental MathMath
Measurement Estimation – Measurement Estimation – LengthLength
Measurement Estimation – Measurement Estimation – Length StrategiesLength Strategies
• There are 2 measurement estimation – length strategies – Benchmark Centimetre– Benchmark Metre
Benchmark Centimetre Benchmark Centimetre Strategy (Introduction)Strategy (Introduction)
• Students should use personal referents, such as the width of their little fingers for a 1-centimetre benchmark and the width of their hands for a 10-centimetre benchmark.
• Since a ruler is a very common tool in the classroom, it can serve as a benchmark for 30 centimetres.
• Using these benchmarks, students should estimate lengths of objects from 1 cm to 50 cm.
Benchmark Centimetre Benchmark Centimetre Example (Introduction)Example (Introduction)
• Assemble a number of objects and prepare a list of ranges for estimates of the lengths you will ask.– Will the height of a wastebasket be about 35 – 45 cm or
20 – 30 cm?• Assemble a number of objects that will all have lengths
within a reasonable range of values, so you can ask students if the lengths are less than, more than, or about a given measure. – For example, ask students to decide calculator is less
than, more than, or about 10 cm as you display it.• Have students estimate the length of objects by giving
possible answers– For example, ask if an eraser is about 3 cm, 7 cm or 10
cm
Benchmark Centimetre Benchmark Centimetre Reinforcement (Day 1)Reinforcement (Day 1)
• Question # 1:• Is a piece of lined paper 20 – 30 cm
wide or 40 – 50 cm wide?
Benchmark Centimetre Benchmark Centimetre Reinforcement (Day 1 cont.)Reinforcement (Day 1 cont.)
• Answer:
Benchmark Centimetre Benchmark Centimetre Reinforcement (Day 1 cont.)Reinforcement (Day 1 cont.)
• Question # 2:• Is the waste basket 35 - 45 cm high
or 15 to 25 cm high?
Benchmark Centimetre Benchmark Centimetre Reinforcement (Day 1 cont.)Reinforcement (Day 1 cont.)
• Answer:
Benchmark Centimetre Benchmark Centimetre Reinforcement (Day 1 cont.)Reinforcement (Day 1 cont.)
• Question # 3:• Is a text book 5 – 10 cm think or 15 -
20 cm think?
Benchmark Centimetre Benchmark Centimetre Reinforcement (Day 1 cont.)Reinforcement (Day 1 cont.)
• Answer:
END OF LESSONEND OF LESSON
Benchmark Centimetre Benchmark Centimetre Reinforcement (Day 2)Reinforcement (Day 2)
• Question # 1: • Is a new pencil more, less or about
10 cm long?
Benchmark Centimetre Benchmark Centimetre Reinforcement (Day 2 cont.)Reinforcement (Day 2 cont.)
• Answer:
Benchmark Centimetre Benchmark Centimetre Reinforcement (Day 2 cont.)Reinforcement (Day 2 cont.)
• Question # 2:• Is the top of your desk more, less, or
about 30 cm wide?
Benchmark Centimetre Benchmark Centimetre Reinforcement (Day 2 cont.)Reinforcement (Day 2 cont.)
• Answer:
Benchmark Centimetre Benchmark Centimetre Reinforcement (Day 2 cont.)Reinforcement (Day 2 cont.)
• Question # 3:• Is your hand more, less or about 10
cm wide
Benchmark Centimetre Benchmark Centimetre Reinforcement (Day 2 cont.)Reinforcement (Day 2 cont.)
• Answer:
Benchmark Centimetre Benchmark Centimetre Reinforcement (Day 2 cont.)Reinforcement (Day 2 cont.)
• Question # 4:• Is a text book more, less or about 40
cm wide?
Benchmark Centimetre Benchmark Centimetre Reinforcement (Day 2 cont.)Reinforcement (Day 2 cont.)
• Answer:
Benchmark Centimetre Benchmark Centimetre Reinforcement (Day 2 cont.)Reinforcement (Day 2 cont.)
• Question # 5:• Is your arm more, less, or about 30
cm long?
Benchmark Centimetre Benchmark Centimetre Reinforcement (Day 2 cont.)Reinforcement (Day 2 cont.)
• Answer:
END OF LESSONEND OF LESSON
Benchmark Centimetre Benchmark Centimetre Reinforcement (Day 3)Reinforcement (Day 3)
• Question # 1:• Is CD about 15 cm, 20 cm or 25 cm
wide?
Benchmark Centimetre Benchmark Centimetre Reinforcement (Day 3 cont.)Reinforcement (Day 3 cont.)
• Answer:
Benchmark Centimetre Benchmark Centimetre Reinforcement (Day 3 cont.)Reinforcement (Day 3 cont.)
• Question # 2:• Is a piece of lined paper about 25
cm, 35 cm or 45 cm wide?
Benchmark Centimetre Benchmark Centimetre Reinforcement (Day 3 cont.)Reinforcement (Day 3 cont.)
• Answer:
Benchmark Centimetre Benchmark Centimetre Reinforcement (Day 3 cont.)Reinforcement (Day 3 cont.)
• Question # 3:• Is an apple about 10 cm, 20 cm or 30
cm wide?
Benchmark Centimetre Benchmark Centimetre Reinforcement (Day 3 cont.)Reinforcement (Day 3 cont.)
• Answer:
Benchmark Centimetre Benchmark Centimetre Reinforcement (Day 3 cont.)Reinforcement (Day 3 cont.)
• Question # 4:• Is a new pencil about 10 cm, 20 cm
or 30 cm long?
Benchmark Centimetre Benchmark Centimetre Reinforcement (Day 3 cont.)Reinforcement (Day 3 cont.)
• Answer:
Benchmark Centimetre Benchmark Centimetre Reinforcement (Day 3 cont.)Reinforcement (Day 3 cont.)
• Question # 5:• Is an iPad about 25 cm, 35 cm or 50
cm wide?
Benchmark Centimetre Benchmark Centimetre Reinforcement (Day 3 cont.)Reinforcement (Day 3 cont.)
• Answer:
END OF LESSONEND OF LESSON
Benchmark Centimetre Benchmark Centimetre Reinforcement (Day 4)Reinforcement (Day 4)
• Question # 1:• About how wide is a your math text
book?
Benchmark Centimetre Benchmark Centimetre Reinforcement (Day 4 cont.)Reinforcement (Day 4 cont.)
• Answer:
Benchmark Centimetre Benchmark Centimetre Reinforcement (Day 4 cont.)Reinforcement (Day 4 cont.)
• Question # 2:• About how long is a pencil?
Benchmark Centimetre Benchmark Centimetre Reinforcement (Day 4 cont.)Reinforcement (Day 4 cont.)
• Answer:
Benchmark Centimetre Benchmark Centimetre Reinforcement (Day 4 cont.)Reinforcement (Day 4 cont.)
• Question # 3:• About how tall is a waste basket?
Benchmark Centimetre Benchmark Centimetre Reinforcement (Day 4 cont.)Reinforcement (Day 4 cont.)
• Answer:
Benchmark Centimetre Benchmark Centimetre Reinforcement (Day 4 cont.)Reinforcement (Day 4 cont.)
• Question # 4:• About how thick is a text book?
Benchmark Centimetre Benchmark Centimetre Reinforcement (Day 4 cont.)Reinforcement (Day 4 cont.)
• Answer:
Benchmark Centimetre Benchmark Centimetre Reinforcement (Day 4 cont.)Reinforcement (Day 4 cont.)
• Question # 5:• About how wide is your finger?
Benchmark Centimetre Benchmark Centimetre Reinforcement (Day 4 cont.)Reinforcement (Day 4 cont.)
• Answer:
END OF LESSONEND OF LESSON
Benchmark Centimetre Benchmark Centimetre Assessment (Day 5)Assessment (Day 5)
• Question # 1:• Is a new pencil about 10 cm, 20 cm
or 30 cm long?
Benchmark Centimetre Benchmark Centimetre Assessment (Day 5 cont.)Assessment (Day 5 cont.)
• Answer:
Benchmark Centimetre Benchmark Centimetre Assessment (Day 5 cont.)Assessment (Day 5 cont.)
• Question # 2:• About how wide is a piece of paper?
Benchmark Centimetre Benchmark Centimetre Assessment (Day 5 cont.)Assessment (Day 5 cont.)
• Answer:
Benchmark Centimetre Benchmark Centimetre Assessment (Day 5 cont.)Assessment (Day 5 cont.)
• Question # 3:• About how long is your shoe?
Benchmark Centimetre Benchmark Centimetre Assessment (Day 5 cont.)Assessment (Day 5 cont.)
• Answer:
Benchmark Centimetre Benchmark Centimetre Assessment (Day 5 cont.)Assessment (Day 5 cont.)
• Question # 4:• Is your hand more, less or about 10
cm wide
Benchmark Centimetre Benchmark Centimetre Assessment (Day 5 cont.)Assessment (Day 5 cont.)
• Answer:
Benchmark Centimetre Benchmark Centimetre Assessment (Day 5 cont.)Assessment (Day 5 cont.)
• Question # 5:• About how wide is an apple?
Benchmark Centimetre Benchmark Centimetre Assessment (Day 5 cont.)Assessment (Day 5 cont.)
• Answer:
END OF LESSONEND OF LESSON
Benchmark Metre Strategy Benchmark Metre Strategy (Introduction)(Introduction)
• Since most door handles are about 1 metre above the floor, students could use this distance as a benchmark for 1 metre.
• They could use their arm span when their arms are opened wide.
• Students should be able to measure lengths from 1 to 20 metres
Benchmark Metre Example Benchmark Metre Example (Introduction)(Introduction)
• Use more, less or about questions– For example, is the window more, less or
about 2 m wide
• Use a pre-determined list– For example, is the room 3 m, 7 m, or 10
m wide?
• Use distances of objects– For example, asked students how far away
something lies, 1-2 m, 3-4 m, or 5-6 m
Benchmark Metre Benchmark Metre Reinforcement (Day 1)Reinforcement (Day 1)
• Question # 1:• Is your desk more, less, or about 2
m?
Benchmark Metre Benchmark Metre Reinforcement (Day 1 cont.)Reinforcement (Day 1 cont.)
• Answer:
Benchmark Metre Benchmark Metre Reinforcement (Day 1 cont.)Reinforcement (Day 1 cont.)
• Question # 2:• Is the classroom ceiling more, less, or
about 10 m high?
Benchmark Metre Benchmark Metre Reinforcement (Day 1 cont.)Reinforcement (Day 1 cont.)
• Answer:
Benchmark Metre Benchmark Metre Reinforcement (Day 1 cont.)Reinforcement (Day 1 cont.)
• Question # 3:• Is the classroom door more, less, or
about 1 m wide?
Benchmark Metre Benchmark Metre Reinforcement (Day 1 cont.)Reinforcement (Day 1 cont.)
• Answer:
END OF LESSONEND OF LESSON
Benchmark Metre Benchmark Metre Reinforcement (Day 2)Reinforcement (Day 2)
• Question # 1:• Are you more, less or about 3 m tall?
Benchmark Metre Benchmark Metre Reinforcement (Day 2 cont.)Reinforcement (Day 2 cont.)
• Answer:
Benchmark Metre Benchmark Metre Reinforcement (Day 2 cont.)Reinforcement (Day 2 cont.)
• Question # 2:• Is the classroom door about 1 m, 2 m
or 3 m tall?
Benchmark Metre Benchmark Metre Reinforcement (Day 2 cont.)Reinforcement (Day 2 cont.)
• Answer:
Benchmark Metre Benchmark Metre Reinforcement (Day 2 cont.)Reinforcement (Day 2 cont.)
• Question # 3:• Is your desk about 1 m, 2 m, or 3 m
wide?
Benchmark Metre Benchmark Metre Reinforcement (Day 2 cont.)Reinforcement (Day 2 cont.)
• Answer:
Benchmark Metre Benchmark Metre Reinforcement (Day 2 cont.)Reinforcement (Day 2 cont.)
• Question # 4:• Is your classroom 5 m, 10 m, or 20 m
wide?
Benchmark Metre Benchmark Metre Reinforcement (Day 2 cont.)Reinforcement (Day 2 cont.)
• Answer:
Benchmark Metre Benchmark Metre Reinforcement (Day 2 cont.)Reinforcement (Day 2 cont.)
• Question # 5:• Most cars are about 5 m, 10 m, or 15
m in length?
Benchmark Metre Benchmark Metre Reinforcement (Day 2 cont.)Reinforcement (Day 2 cont.)
• Answer:
END OF LESSONEND OF LESSON
Benchmark Metre Benchmark Metre Reinforcement (Day 3)Reinforcement (Day 3)
• Question # 1:• About how far away is the next desk
from you, 1-2 m, 3-4 m or 5-6 m?
Benchmark Metre Benchmark Metre Reinforcement (Day 3 cont.)Reinforcement (Day 3 cont.)
• Answer:
Benchmark Metre Benchmark Metre Reinforcement (Day 3 cont.)Reinforcement (Day 3 cont.)
• Question # 2:• About how tall is the classroom
ceiling, 3-4 m, 5-6 m or 7-8 m?
Benchmark Metre Benchmark Metre Reinforcement (Day 3 cont.)Reinforcement (Day 3 cont.)
• Answer:
Benchmark Metre Benchmark Metre Reinforcement (Day 3 cont.)Reinforcement (Day 3 cont.)
• Question # 3:• About how wide is the class room, 5-
6 m, 10-12 m or 19-20 m?
Benchmark Metre Benchmark Metre Reinforcement (Day 3 cont.)Reinforcement (Day 3 cont.)
• Answer:
Benchmark Metre Benchmark Metre Reinforcement (Day 3 cont.)Reinforcement (Day 3 cont.)
• Question # 4:• About how wide is the projection
screen in the classroom, 2-3 m, 5-6 m or 8-9 m?
Benchmark Metre Benchmark Metre Reinforcement (Day 3 cont.)Reinforcement (Day 3 cont.)
• Answer:
Benchmark Metre Benchmark Metre Reinforcement (Day 3 cont.)Reinforcement (Day 3 cont.)
• Question # 5:• About how tall is a book shelf, 1-2 m,
3-4 m, or 5-6 m?
Benchmark Metre Benchmark Metre Reinforcement (Day 3 cont.)Reinforcement (Day 3 cont.)
• Answer:
END OF LESSONEND OF LESSON
Benchmark Metre Benchmark Metre Reinforcement (Day 4)Reinforcement (Day 4)
• Question # 1:• About how many metres wide is the
white board?
Benchmark Metre Benchmark Metre Reinforcement (Day 4 cont.)Reinforcement (Day 4 cont.)
• Answer:
Benchmark Metre Benchmark Metre Reinforcement (Day 4 cont.)Reinforcement (Day 4 cont.)
• Question # 2:• About how many metres tall is the
white board?
Benchmark Metre Benchmark Metre Reinforcement (Day 4 cont.)Reinforcement (Day 4 cont.)
• Answer:
Benchmark Metre Benchmark Metre Reinforcement (Day 4 cont.)Reinforcement (Day 4 cont.)
• Question # 3:• About how many metres is the office
from your classroom door?
Benchmark Metre Benchmark Metre Reinforcement (Day 4 cont.)Reinforcement (Day 4 cont.)
• Answer:
Benchmark Metre Benchmark Metre Reinforcement (Day 4 cont.)Reinforcement (Day 4 cont.)
• Question # 4:• About how many metres wide is the
classroom?
Benchmark Metre Benchmark Metre Reinforcement (Day 4 cont.)Reinforcement (Day 4 cont.)
• Answer:
Benchmark Metre Benchmark Metre Reinforcement (Day 4 cont.)Reinforcement (Day 4 cont.)
• Question # 5:• About how many metres tall is the
classroom ceiling?
Benchmark Metre Benchmark Metre Reinforcement (Day 4 cont.)Reinforcement (Day 4 cont.)
• Answer:
END OF LESSONEND OF LESSON
Benchmark Metre Assessment Benchmark Metre Assessment (Day 5)(Day 5)
• Question # 1:• Is your classroom 5 m, 10 m, or 20 m
wide?
Benchmark Metre Assessment Benchmark Metre Assessment (Day 5 cont.)(Day 5 cont.)
• Answer:
Benchmark Metre Assessment Benchmark Metre Assessment (Day 5 cont.)(Day 5 cont.)
• Question # 2:• About how wide is the projection
screen in the classroom, 2-3 m, 5-6 m or 8-9 m?
Benchmark Metre Assessment Benchmark Metre Assessment (Day 5 cont.)(Day 5 cont.)
• Answer:
Benchmark Metre Assessment Benchmark Metre Assessment (Day 5 cont.)(Day 5 cont.)
• Question # 3:• About how many metres tall is the
classroom ceiling?
Benchmark Metre Assessment Benchmark Metre Assessment (Day 5 cont.)(Day 5 cont.)
• Answer:
Benchmark Metre Assessment Benchmark Metre Assessment (Day 5 cont.)(Day 5 cont.)
• Question # 4:• About how many metres wide is your
desk?
Benchmark Metre Assessment Benchmark Metre Assessment (Day 5 cont.)(Day 5 cont.)
• Answer:
Benchmark Metre Assessment Benchmark Metre Assessment (Day 5 cont.)(Day 5 cont.)
• Question # 5:• About how many metres tall is the
classroom door?
Benchmark Metre Assessment Benchmark Metre Assessment (Day 5 cont.)(Day 5 cont.)
• Answer:
END OF LESSONEND OF LESSON
Measurement Estimation – Measurement Estimation – Length Summative AssessmentLength Summative Assessment
• Question # 1:• About how wide is the projection
screen in the classroom, 2-3 m, 5-6 m or 8-9 m?
Measurement Estimation – Measurement Estimation – Length Summative AssessmentLength Summative Assessment
• Answer:
Measurement Estimation – Measurement Estimation – Length Summative AssessmentLength Summative Assessment
• Question # 2:• About how tall is a waste basket?
Measurement Estimation – Measurement Estimation – Length Summative AssessmentLength Summative Assessment
• Answer:
Measurement Estimation – Measurement Estimation – Length Summative AssessmentLength Summative Assessment
• Question # 3:• About how many metres is the office
from your classroom door?
Measurement Estimation – Measurement Estimation – Length Summative AssessmentLength Summative Assessment
• Answer:
Measurement Estimation – Measurement Estimation – Length Summative AssessmentLength Summative Assessment
• Question # 4:• Is a piece of lined paper 20 – 30 cm
wide or 40 – 50 cm wide?
Measurement Estimation – Measurement Estimation – Length Summative AssessmentLength Summative Assessment
• Answer:
Measurement Estimation – Measurement Estimation – Length Summative AssessmentLength Summative Assessment
• Question # 5:• Is the top of your desk more, less, or
about 30 cm wide?
Measurement Estimation – Measurement Estimation – Length Summative AssessmentLength Summative Assessment
• Answer:
END OF LESSONEND OF LESSON