Adding ten changes only the tens digit. That has not changed with bigger numbers.
Step 1: Let's Learn
Read it, or press Listen and follow the words.
An example
Ten more than 342 is 352. The 3 and the 2 do not move.
When it rolls over
Ten more than 395 is 405. Nine tens and one more ten make a new hundred.
Ten more moves one digit
Adding ten to 342 gives 352. The ones digit did not move and neither did the hundreds. Only the tens digit went up by one, because you added exactly one ten. Seeing this makes the answer instant instead of something to count out.
The case where more than one digit moves
Ten more than 395 is not 3-10-5. The tens digit was already 9, so adding one more ten fills it: ten tens bundle into a hundred. The answer is 405. Whenever the tens digit is 9, expect the hundreds digit to change too.
Ten less works the same in reverse
Ten less than 342 is 332 — the tens digit drops by one. And ten less than 405 is 395, where you had to open a hundred to find a ten to remove. The rollover cases are the ones worth practising; the plain ones look after themselves.
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 Ana Add a Ten
Ana works out ten more than 267.
- Step 1
She holds the hundreds and ones still: a 2 and a 7.
Step 4: Your Turn
Practice makes it stick.
The Collection
Problem 1 of 2
Leo has 428 stamps and buys 10 more. How many now?
stamps
Giving Some Away
Problem 2 of 2
Ana has 561 beads and gives away 10. How many are left?
beads
Ten More, Ten Less
1 of 4
Ten more than 315 is?
2 of 4
Ten less than 682 is?
3 of 4
Ten more than 495 is?
4 of 4
Ten less than 703 is?
Step 5: Quick Check
Show what you know.
Question 1 of 2
Ten more than 236 is?
Question 2 of 2
Ten more than 390 is?
What You Learned
- Ten more changes only the tens digit.
- Unless the tens are full, and then a hundred is made.
- You can do this in your head.