Question

I need help finding and understanding two strategies for 435+290 for a 2nd grader.

Answer 1

You could use algorithm
Or
400+200=600
30+90=120
0+5=5

725

Answer 2

well, you should start off by separating the hundreds, tens and ones. So its 400, 30, and 5. 200 and 90. Then add, awnser is 725