A hundred more works like ten more, one place further left.
Step 1: Let's Learn
Read it, or press Listen and follow the words.
An example
A hundred more than 342 is 442. The 4 and the 2 do not move.
Compare the two
Ten more changes the middle digit. A hundred more changes the first one.
One column further left
A hundred more than 342 is 442. The tens and ones are untouched; only the hundreds digit rises by one. It is the same idea as ten more, moved one place to the left, which is what makes our number system so learnable — the rules repeat.
When the hundreds column fills
A hundred more than 912 would need a 10 in the hundreds place, which is not allowed. Ten hundreds bundle into a thousand, so the answer is 1,012. In Grade 2 you meet this rarely, but knowing why it happens means it will not surprise you later.
Why these count as mental maths
Ten more, ten less, a hundred more and a hundred less should not need paper. They are single-digit changes in a known column. Doing them in your head builds the place-value sense that written addition depends on.
Step 2: Try It Yourself
Tap and try it out.
Hundreds
3
Tens
4
Ones
2
3 hundreds, 4 tens and 2 ones is 342.
Step 3: Watch an Example
One step at a time.
Watch Leo Add a Hundred
Leo works out a hundred more than 617.
- Step 1
He holds the tens and ones still: a 1 and a 7.
Step 4: Your Turn
Practice makes it stick.
The Fundraiser
Problem 1 of 2
A school has raised 254 pounds and gets 100 more. How much now?
pounds
Spending
Problem 2 of 2
A shop had 738 apples and sold 100. How many are left?
apples
A Hundred Either Way
1 of 4
A hundred more than 415 is?
2 of 4
A hundred less than 862 is?
3 of 4
Ten more than 380 is?
4 of 4
A hundred more than 209 is?
Step 5: Quick Check
Show what you know.
Question 1 of 2
A hundred more than 546 is?
Question 2 of 2
Which digit changes when you add 100?
What You Learned
- A hundred more changes only the hundreds digit.
- Ten more changes only the tens digit.
- Knowing which digit to move is the whole trick.