Posted by Julie on .
Writing in Math  How can estimating help you add twodigit numbers?

3rd grade Math 
Mika,
Benchmark numbers are easier to addusually ending in 0's or 5's.
Ex:
28+31 can be turned into 30+30. 28 was rounded up to 30, and 31 was rounded down to 30.
4 and lower is rounded down; 5 and higher is rounded up. If the number is 3,4,5,6 or 7 it is rounded to five, if you're getting more specific.
I hope this helps; but I'm only in 6th grade so I'm not sure (: 
3rd grade Math 
david heras,
how can estimating help you add two digit numbers