When you split a teen number, one part is always 10.
Step 1: Let's Learn
Read it, or press Listen and follow the words.
A bond with ten in it
15 splits into 10 and 5. The ten part never changes.
15
10
5
- 10 + 5 = 15
- 5 + 10 = 15
- 15 − 10 = 5
- 15 − 5 = 10
All four use the same three numbers: 10, 5, and 15.
Ten part
Ones part
Breaking apart and building are one skill
Splitting 16 into 10 and 6 is the same knowledge as building 16 from 10 and 6. Practise both so either direction is available.
This is the move behind take-from-ten
To do 16 − 9 you first break 16 into 10 and 6. Breaking apart is not busywork; it is step one of a method you need soon.
Step 2: Try It Yourself
Tap and try it out.
16
10
6
- 10 + 6 = 16
- 6 + 10 = 16
- 16 − 10 = 6
- 16 − 6 = 10
All four use the same three numbers: 10, 6, and 16.
Ten part
Step 3: Watch an Example
One step at a time.
Watch Ana Split 18
Ana splits 18 into two parts.
- Step 1
She knows one part must be the ten.
Step 4: Your Turn
Practice makes it stick.
Splitting Sweets
Problem 1 of 1
Mia has 17 sweets. She puts 10 in a bag. How many are left out?
sweets
Ten and What?
Take the ten out and see what is left.
1 of 2
14 is 10 and what?
2 of 2
19 is 10 and what?
Step 5: Quick Check
Show what you know.
Question 1 of 2
12 is 10 and what?
Question 2 of 2
16 is 10 and what?
What You Learned
- A teen number always splits into 10 and some ones.
- The ten part never changes.
- Only the ones part is different each time.