3rd grade
posted by amanda on .
Use compatible numbers to complete this problem. Then estimate the sum.
3,428
+432
_____

What numbers are 3428 and 432 fairly close to? Once you come up with those, then you should be able to add in your head and estimate the answer.
3428  fairly close to 3400
432  fairly close to 450
When you add those two in your mind, you should get 3850. 
3860