Australian Curriculum Indicator YR 6 Add and subtract decimals, with and without digital technologies, and use es5ma5on and rounding to check the reasonableness of answers (ACMNA128). Key Ideas: • Understand that the base 10 number system can be
extended to thousandths (to the right the units are decreasing in value in powers of 10-‐ 1, ).
• There are numbers between consecu5ve whole numbers (1.1., 1.2, 1.3).
• Understand that numbers are par55oned into smaller and smaller units when working with decimals and frac5ons.
• Understand how decimal numbers to thousandth can be added and subtracted.
• Use digital technologies to assist applica5on. • Explore es5ma5on and rounding to check for
reasonableness of answers. Context for Learning -‐ Real life experiences: Decimals are used widely in everyday situa5ons that involve money and measurement. Resources FISH, paper, place value chart (laminated), decimal frac5on , 100ths flip pack, laminated hundred grid (0.01-‐1), laminated blank number line,
Vocabulary Decimal, place value, tenths, hundredths, thousandths,
decimal point, whole numbers,
rounding, es5ma5ng, comparing, ordering, reasonableness, consecu5ve, conversion, vinculum, denominator, numerator, ascending, descending. Introductory Ac@vity Process Learning inten5on: Re-‐visit numerator, denominator and vinculum (the vinculum refers to-‐out of or divisor). Students can match and order equivalent common frac5ons with decimal frac5ons to tenths. Students work in small groups of four. Make It Use a strip of paper to display 10/10. Students can discuss how to achieve this. Teacher models the language of frac5ons-‐this is a whole with 10 parts. Label sec5ons using common frac5ons (1/10-‐10/10). AVer labelling, cut each sec5on into individual cards. Write It : Using their common frac5on cards, students will then transfer the number of tenths on each card onto a place value chart using decimals. Each group will then write the decimal frac5on onto the back of their common frac5on card to show the equivalent. Explain It: Using the FISH heuris5c the group explains • How did they fold their paper strips • Are there any whole numbers? Why not? • What does 10/10 mean? • What evidence do you have to demonstrate this? • What does it look like on the place value chart? Forma4ve Assessment: Checkout Strategy The Checkout Strategy is a transi5onal ac5vity that can be used for forma5ve assessment. It could be as learners leaves the classroom or moves to another ac5vity. A quick, simple ques5on or task is given to them and the teacher observes their level of understanding on a given topic. As examples, learners could show their answer on their whiteboards, write it on a s5cky note or orally explain on their way out.)
Individually, students will choose one of their common frac5on cards. Place their card on a number line provided (with intervals) showing the common frac5on and saying the equivalent decimal frac5on. Learners capture their completed number lines using an iPad (if available) Individual learners show and tell their work on an IWB as quick observa5ons of success – Green Fish thinking Ac@vity Processes-‐ Sequencing Decimal Number PaIerns Learning inten5on: Students can iden5fy pa^erns in decimal numbers and transfer this knowledge to an algorithm. Make It: Students have a laminated decimal frac5on grid-‐ 0.1, 0.2, 0.3…...10.0 10 more than that number. Con5nue to a given number (e.g. 6.0). Checkout-‐ Hold up charts displaying pa^ern. Write It: On their place value charts, write one of the coloured numbers. What did we add? Write that on the place value chart underneath the first number. Add both decimal frac5ons. Is this number coloured on the grid pa^ern? Explain It: Explain the rela5onship between the sequence and pa^ern on the grid and the algorithm on the place value chart. Repeat ac5vity with different addi5ons. Repeat ac5vity using subtrac5on. Ac@vity Processes-‐Sequencing Explicit teaching: Whole class Revisit ordering of decimal frac5ons up to 10. Have learners place decimal frac5on cards on a number line (Blue floor mat) on the floor without integers. Learning inten@on: Students can match and order equivalent common frac@ons with decimal frac@ons to hundredths. Students work in small groups using the FISH heuris5c. Make It: Each group is given a 100ths flip pack. -‐ Write It: Each student randomly chooses a common frac5on and mentally converts it to a decimal frac5on and writes it on the place value chart. Within their group, students order their frac5ons in ascending or descending order.
Explain It: Explain group findings by answering the following ques5ons: • How many hundredths do we need to add, to make
one whole? Checkout Strategy Name a frac5on that is more than 30/100 in its simplest form. Ac@vity Processes-‐Adding and Subtrac@ng Decimals on a Place Value Chart Learning inten4on: Learners can iden5fy pa^erns in decimal numbers and transfer this knowledge to an algorithm. Make It: Students have a laminated A3 decimal frac5on grid-‐ 0.01, 0.02, 0.03…...1.0 Colour a given pa^ern-‐ e.g. start at 0.06 and colour the decimal frac5on that is 4/100 more than that number. Con5nue to a given number. Checkout Strategy-‐ Class together holds up charts displaying pa^ern. Write It: On their place value charts, write one of the coloured numbers. What did we add? Write that on the place value chart underneath the first number. Add both decimal frac5ons. Is this number coloured on the grid pa^ern? Explain It: Explain the rela5onship between the sequence and pa^ern on the grid and the algorithm on the place value chart.
Mathema5cians use their number sense to understand a problem
Repeat ac5vity with different addi5ons. Repeat ac5vity using subtrac5on. Ac@vity Processes-‐ Decimal Sequences on a Number Line Learning inten5on: Learners will place decimal numbers between consecu5ve whole numbers on a number line. Make It: Teacher unpacks the word calibrated and demonstrates on a number line, physical or digital how to record whole numbers with a calibrated scale. Learners are prompted to discuss integers, coun5ng forward and backwards along the number line In pairs, students use a blank laminated number line, they marked in tenths (using a whiteboard maker) and are given a range between a set of whole numbers. Star5ng at 0, mark the integers in the scale. Using the jump strategy, h^ps://www.det.nsw.edu.au/eppcontent/glossary/app/resource/factsheet/4018.pdf Star5ng at a given number, move backwards and forwards to solve an addi5on or subtrac5on equa5ons0.0 / . Write It: Pairs of learners record their number sequence iden5fying the rule in the pa^ern (e.g. 1.2, 1.4, 1.6 Rule: + 0.2) One number is selected and wri^en on a place value chart an integer is added underneath and totalled together (e.g. 1.2 + 0.2 ) Repeat this ac5vity, selec5ng different sequencing rules (forwards and backwards). Explain It: Learners in pairs explain to the class how the jump strategy was used to create their algorithm on the place value chart.
Extensions and Varia@ons (Differen@a@on) Learning inten@on: Learners can add and subtract decimal numbers and iden5fy the correct place of a decimal frac5on on a number line (while teacher works with a focus group) h^p://www.studyladder.com.au/teacher/resources/ac5vity?ac5vity_id=22222 Adding and Subtrac5ng Decimals h^p://www.studyladder.com.au/play/ac5vity-‐new/id/21322 Adding and Subtrac5ng Decimals h^p://www.studyladder.com.au/teacher/resources/ac5vity?ac5vity_id=21483 Decimals on a Number Line Differen@a@on: Focus Group: Learners who are iden5fied through forma5ve assessment (checkout strategy and observa5ons) as not yet understanding the intended learning, will go into a focus group. The focus group, learning will be focused on the gaps iden5fied in class. Focus ac5vi5es will start with tenths and then progress. Inves@ga@on: Quality not quan@ty Learners look at the weather sec5on of a newspaper and record the maximum and minimum temperatures of a city over a two week period. Learners plot the informa5on on a line graph. As a group • Order the maximum temperatures, lowest to highest on a number line • Repeat for minimum temperatures • Find the average minimum and maximum Individually • Explain, any other pa^erns from this inves5ga5on that explain something about the weather in a
given city? Assessment-‐Where in the learning cycle? Forma5ve assessment-‐ checkouts, explana5on it opportuni5es, number lines Summa5ve Assessment-‐ adding and subtrac5ng algorithms, crea5ng a number line. Background An essen5al element to this MAG is a REVISIT and CONSOLIDATION of student knowledge and understandings of common frac5ons, tenths, hundredths and thousandths, and how they are represented on a PLACE VALUE Chart. Students will work through from tenths, to hundredths, and then to thousandths, developing an ability to par55on into smaller and smaller units mul5plica5vely (each par55oning is one-‐tenth of the previous one – Base 10 System).