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## Arithmetic

### Course: Arithmetic>Unit 6

Lesson 2: Strategies for adding within 1,000

# Addition using groups of 10 and 100

Sal rewrites addition problems to make them easier to solve.

## Want to join the conversation?

• What is 555+795=? I don't really get it.

Write the two numbers one on top of the other, lining up the digits.

555
+ 795
------

Add the digits in the ones place (5 + 5 = 10). Write down the 0 and carry the 1 to the tens place.

555
+ 795
------
0

Add the digits in the tens place, including the carried digit (1 + 5 + 9 = 15). Write down the 5 and carry the 1 to the hundreds place.

555
+ 795
------
50

Add the digits in the hundreds place, including the carried digit (1 + 7 = 8).

555
+ 795
------
1350

So, 555 + 795 = 1350.
• How would this work when adding thousands?
• Similar to the first question in the video at , 632 + 4278 could be done like this:
(630+2)+4278
630+(2+4278)
630+4280

This equals 4,910. It's a bit more difficult in the thousands, but it can still be done in the same way.
• can you round 100?