My daughter brought home this question:
How does knowing 28=30-2 help you find 13+28?
Any ideas?
3 answers
Because then you can figure out what 11 more than 30 is. That is easier than trying to add 13 and 28 in your head.
Yes, it is a matter of grouping:
13+ 28= (11+2)+28= 11 + (2+28)= 11+30
13+ 28= (11+2)+28= 11 + (2+28)= 11+30
length in feet and inches