In Chapter 5 you made a ten to add. The same move works here.
Step 1: Let's Learn
Read it, or press Listen and follow the words.
Get to the next ten first
28 + 5. 28 needs 2 to reach 30. Take 2 from the 5, and 3 is left.
Then it is easy
30 + 3 = 33. So 28 + 5 = 33.
The same make-ten move, bigger numbers
28 + 5 becomes 30 + 3. You give 28 the two it needs to reach a ten, and the five has three left.
Why aim at the next ten
Numbers ending in zero are the easiest to add to. Getting to one is worth the small detour.
Step 2: Try It Yourself
Tap and try it out.
First number
and Add ones
Altogether
Tens
2
Ones
13
28 + 5 = 33
There are 13 loose ones. Ten of them can become one more ten.
Step 3: Watch an Example
One step at a time.
Watch Ana Make Thirty
Ana works out 28 + 5.
- Step 1
She asks what 28 needs to reach 30. The answer is 2.
Step 4: Your Turn
Practice makes it stick.
Beads
Problem 1 of 1
Leo has 29 beads. He adds 4 more. How many now?
beads
Reach the Next Ten
1 of 3
18 + 5 = ?
2 of 3
27 + 6 = ?
3 of 3
26 + 8 = ?
Step 5: Quick Check
Show what you know.
Question 1 of 2
29 + 5 = ?
Question 2 of 2
What does 27 need to reach 30?
What You Learned
- Get to the next ten first.
- Split the second number to do it.
- 28 + 5 is 30 + 3, which is 33.