Tens go with tens. Ones go with ones. That is the whole method.
Step 1: Let's Learn
Read it, or press Listen and follow the words.
An example
43 + 25. Tens: 4 and 2 make 6 tens. Ones: 3 and 5 make 8 ones. The answer is 68.
Either order works
You can add the ones first if you prefer. Tens first usually keeps the numbers tidier.
Why like goes with like
When you add 34 + 25 you add the tens together and the ones together, because a ten and a one are different sizes. You cannot combine three tens and five ones into one count any more than you can add three boxes to five apples. Keeping the columns separate is what makes the method work.
A worked case: 34 + 25
Break both numbers up: 34 is 30 + 4, and 25 is 20 + 5. Add the tens: 30 + 20 = 50. Add the ones: 4 + 5 = 9. Put them back together: 50 + 9 = 59. Every written method you meet later is a shorthand for exactly these steps.
Which column first
In this decomposed method you can start with either column and get the same answer. In the written column method you start with the ones, because that is the direction a carry travels. Knowing why the order changes stops the written method feeling arbitrary.
Step 2: Try It Yourself
Tap and try it out.
First number
and Second number
Altogether
Tens
6
Ones
8
43 + 25 = 68
4 tens and 2 tens make 6 tens. Ones go with ones.
Step 3: Watch an Example
One step at a time.
Watch Ana Add 43 and 25
Ana has 43 and 25 to add.
- Step 1
She counts the rods: 4 and 2 makes 6 rods.
Step 4: Your Turn
Practice makes it stick.
Two Classes
Problem 1 of 2
One class collected 32 tins and another collected 46. How many tins in all?
tins
The Long Walk
Problem 2 of 2
Leo walked 51 metres, then 24 metres more. How far did he walk?
metres
Tens First, Then Ones
1 of 4
34 + 25 = ?
2 of 4
52 + 36 = ?
3 of 4
61 + 27 = ?
4 of 4
45 + 30 = ?
Step 5: Quick Check
Show what you know.
Question 1 of 2
23 + 41 = ?
Question 2 of 2
What goes with the tens?
What You Learned
- Add the tens to the tens.
- Add the ones to the ones.
- Then say the answer as tens and ones.