Why 10?

Why 10? Our number system is based and built by 10’s. It originated because we have 10 fingers—how the first person began counting.

Presented by Joan Kernan and Donna Kouri

Research for Number SenseNational Council for Mathematics

Elementary and Middle School Mathematics: Teaching Developmentally Student should:

Understand numbers, ways of representing numbers, relationships among numbers, and number systems

Understand meanings of operations and how they relate to one another

Compute fluently and make reasonable estimates

Research for Number SenseKey ideas include:

Recognize “how many” in a set (Cardinality) Decomposing - Examples 7 is composed of 4 and 3 as

well as 5 and 2, is less than 9 and more than 5, is 3 away from 10, can be recognized quickly, will extend to the understanding of 17, 57, and 370

Encounter a variety of meanings for addition and subtraction

Fluency requires a balance and connection between conceptual understanding and computational proficiency

Subitizing and Seeing NumbersWe will be looking closely at numbers, and how much each number is worth; what makes that number that number.

This session is designed to help young elementary children see numbers within numbers. The goal is NOT to master these techniques within one math lesson.

The games today will strengthen the child’s understanding of the values of numbers.

This is playing with numbers and learning during the journey.

Subitizing

The idea of Seeing Numbers is the ability to recognize the value of a number without counting.

This is officially known as Subitizing. By seeing numbers as groups rather than the result of counting single units or counting on, children are able to conceptualize groups of numbers and how they can be combined to make new numbers.

Dot Cards

The value of this demonstration:

Large-- need a volunteer distinguish between the immediate known and and the cards with hesitation

Small– individualizing the instruction

Magnetic Two-Sided Counters

• Whole Group Demo

• Focus on questioning strategies for

students

3-D Grid

Shows numbers with one color.

Allows you to look at visual patterns/placement of two-sided counters

3-D GridShow numbers with two different colors

This extends the activity and is using more techniques: visually adding, plus one, etc

Rekenrek

The Rekenrek was designed at the Freudenthal Institute in Holland.

The term Rekenrek means calculating frame or arithmetic rack.

Rekenrek

The Rekenrek may resemble an abacus. The abacus is based

on place value columns.

The Rekenrek features two rows of ten 10 beads and each row is broken into two sets of

five.

Rekenrek• A large Rekenrek can be used in both whole

and small group instruction.

• For varying grade levels, there is a plethora of resources on the web. We found many demonstrations on YouTube.

Make and Take

Rekenreks

You will need:1. Two rectangular boards2. Two chenille stems3. 10 beads of one color4. 10 beads of another color5. 2 stickers to mark the “read the numbers” area

Conclusion

• Any Ahh Ha! Moments?

• Door Prizes … and the winners are…