Question

1. Use the mental math strategy of rounding (for example +1/-1, +2/- 2, +10/-10, or +20/-20) to add the following numbers. Write down how you would change the numbers in your head for each question.

Ex. 27 + 51 28+50=78
a. 41 + 16=
b. 79 + 14=
c 580 + 355=
d. 174 + 620=
e. 378 + 210=

Answer 1

a. 41 + 16=57 40+17= 57
b. 79 + 14=93 80+13= 93
c. 580+355=935 600+335=935
d. 174+620=794 194+600=794
e. 378+210=588 388+200=588


Here you go, hope this helps! :)