#Compose and decompose numbers to 10 how to#

Practice together and check that students can compose numbers. Explain to students that if you can't see the decomposition, you need to count the total and then count on to the given number.

#Compose and decompose numbers to 10 how to#

Practice recognizing numbers on a bead string and discuss which numbers can be switched and how to write them with an arrow. Discuss that you can use an arrow to write down the number bonds.

Also mention that you can switch numbers in a number bond. Explain that sometimes you can already see the decomposition in an image, by color for example. Then show all possible decompositions of 7. Show decomposition by dividing the fish between the two fishbowls. If you already have one of the two numbers, you can count on to the given number. Using the fish, demonstrate that you can decompose the number 6 into 3 and 3, but also in 4 and 2.

Pre-requisite for developing algorithms for finding sums and differences when regrouping is necessary.You can decompose numbers in different ways.

Pre-requisite for developing mental math strategies.

Importance of Composing/Decomposing Numbers

Put your recording slip where it belongs on our graph.

ORGANIZE YOUR WORK How do you know you found all the ways?Ĭomposing/Decomposing Tasks:Building Flexible Thinking About Numbers How many different ways can you make 5 with the fingers on both hands? So What Can We Do? Teach students to conceptualize numbers by composing and decomposing!

For example: 7 + 5 = ? Because I know that 5 is 3 and 2, I can “make 10” : 7 + 3 + 2 = ? 10 + 2 = 12Ģnd Decompose to Add36 + 7 = ? Make the nearest TEN 36 + 7 = ? 36 + 4 + 3 = ? 40 + 3 = 43 Add the TENS then add the ONES 27 + 35 = ? 20 + 7 + 30 + 5 = ? 20 + 30 + 7 + 5 = ? 50 + 12 = 62Ģnd Regroup to Subtract 34 - 6 = ? 2 tens 8 ones HUGE IDEA: 2 tens and 14 ones means the same as 3 tens and 4 ones.

For example: 7can bethought of as five and 2 more or ten and 3 less.

Other numbers can be thought of in relation to them.

FIVEand TEN are important anchor numbers.

Children must be able to name numbers FLEXIBLYin order to have what is called number sense.

The student is expected to : (A)use concrete and pictorial models to compose and decompose numbers up to 1,200 in more than one way as a sum of so many thousands, hundreds, tens, and ones.Ĭomposing and decomposing numbers requires… FLEXIBLE THINKING The student is expected to: (B) use concrete and pictorial models to compose and decompose numbers up to 120 in more than one way as so many hundreds, so many tens, and so many ones.Ģ.2 Number and operations. The student is expected to : (I) compose and decompose numbers up to 10 with objects and pictures.

In April 2012, Texas revised the TEKS in Mathematics… Kinder-2ndKnowledge Statement: The student applies mathematical process standards to understand how to represent and compare whole numbers, the relative position and magnitude of whole numbers, and relationships within the numeration system. Solve one-step and multi-step word problems involving addition and subtraction within 1,000 using a variety of strategies based on place value including algorithms AND….Add up to four two-digit numbers and subtract two-digit numbers using mental strategies and algorithms based on knowledge of place value and properties of operations WHAT?!?!?!?.“Well! That explains why my second graders just don’t get REGROUPING!” Between the ages of 9-12, the brain matures enough to take things apart and put them together in new ways.Composing and Decomposing Numbers Important Pre-Requisite Math Skills based on presentation by Dinah Chancellor, Math Consultant CAMT 2012