There are three columns now. Hundreds with hundreds, tens with tens, ones with ones.
Step 1: Let's Learn
Read it, or press Listen and follow the words.
An example
234 + 152. Hundreds: 3. Tens: 8. Ones: 6. The answer is 386.
While nothing fills up
This is the easy case. Nothing reaches ten, so nothing needs bundling.
Three columns, one rule
Adding 236 + 142 means adding ones to ones, tens to tens, and hundreds to hundreds: 6 + 2 = 8, 30 + 40 = 70, 200 + 100 = 300. Put them together and you have 378. A third column adds work, not difficulty.
Lining the digits up matters more now
With three columns, a digit written slightly off can land in the wrong place and change the answer by ninety or nine hundred. Write on squared paper, one digit per square, ones under ones. Neatness here is not fussiness — it is accuracy.
Estimate with the hundreds
Before adding 236 + 142, notice it is roughly 200 + 100 = 300, so expect an answer in the three hundreds. If you get 78 or 3,078 you know a digit slipped. The hundreds digit alone gives a useful sanity check in a second.
Step 2: Try It Yourself
Tap and try it out.
First number
and Second number
Altogether
Hundreds
3
Tens
8
Ones
6
234 + 152 = 386
3 tens and 5 tens make 8 tens. Ones go with ones.
Step 3: Watch an Example
One step at a time.
Watch Leo Add 234 and 152
Leo has 234 and 152 to add.
- Step 1
He counts the flats: 2 and 1 makes 3.
Step 4: Your Turn
Practice makes it stick.
Two Libraries
Problem 1 of 2
One library has 312 books and another has 245. How many books in all?
books
The Long Drive
Problem 2 of 2
A car drove 421 km, then 253 km more. How far in total?
km
Three Columns
1 of 3
215 + 342 = ?
2 of 3
406 + 271 = ?
3 of 3
523 + 154 = ?
Step 5: Quick Check
Show what you know.
Question 1 of 2
341 + 236 = ?
Question 2 of 2
What goes with the hundreds?
What You Learned
- Three digits means three columns.
- Hundreds with hundreds, tens with tens, ones with ones.
- The rule has not changed at all.