Decomposing and composing to the hundreds place
Decomposing and composing to the hundreds place
8,000 schools use Gynzy
92,000 teachers use Gynzy
1,600,000 students use Gynzy
General
Students learn to decompose and compose numbers to the next hundred from random numbers.
Standards
CCSS.Math.Content.1.NBT.C.4
CCSS.Math.Content.1.NBT.C.5
CCSS.Math.Content.1.NBT.C.6
Learning objective
Students will be able to decompose and compose hundreds (100, 200, 300, ...) from round and random numbers.
Introduction
Complete the number lines with the students. They count in jumps of 1.
Instruction
Explain how to use the MAB blocks to help represent tens and hundreds. When you compose to the next hundred you look to see how many more hundreds you need. Show an example that you can easily compose to a hundred if you know how to compose to a ten. Students complete a number bond chart of 100 with the number bond chart of 10 next to it as support. Explain that when you compose hundreds and tens you need to look to see how many tens you need. When you compose from a tens number to a hundreds number you skip count in tens or hundreds. If you start from a random number you count on to the next ten and then use skip counting. Students practice composing numbers in different ways dragging both money and MAB blocks. Also show how you can show composing by jumps on the number line. Ask them to fill in the missing numbers from a decomposition and then complete the number bond chart. Students need to decompose the numbers in their heads.
To check that students understand decomposing and composing numbers to the nearest 100 you can ask the following questions:
- What can you use as a good example of composing? (money)
- How can you easily compose 200 from 146? (first count on from the ones, then move to tens)
Guided Practice
Students practice composing by dragging money to compose the desired amount. Then they practice decomposing hundreds numbers in a number bond chart without visual support.
Closing
Ask students to fill in the decompositions of 200 and discuss that it is useful to be able to compose to hundreds. Can the students come up with other situations in which this would be useful?
Teaching Tip
Students who have difficulty composing to hundreds can use money or MAB blocks as visual support. They can compose with bills and count on to the desired number. They can do the same with hundreds, tens and ones of MAB blocks.
The online teaching platform for interactive whiteboards and displays in schools
Save time building lessons
Manage the classroom more efficiently
Increase student engagement
Discover more!
About Gynzy
Gynzy is an online teaching platform for interactive whiteboards and displays in schools.
With a focus on elementary education, Gynzy’s Whiteboard, digital tools, and activities make it easy for teachers to save time building lessons, increase student engagement, and make classroom management more efficient.