Sam rode his bike 2/5 of
a mile and walked
another 3/4 of a mile.
how far did he travel?

1.15

Step-by-step explanation:

Looking at the two numbers, we see that the smallest number that both 5 and 4 go into evenly is 20, so our smallest common denominator is 20 and we want to work toward converting our two numbers into twentieths.

Multiply 2/5 x 4/4 = 8/20. 2x4=8 and 5x4=20 (we choose 4/4 because it is equal to 1, and gives us 20 in the denominator.) Any number times one is itself.

Multiply 3/4 x 5/5 = 15/20 (same reasoning for choosing 5/5 as above.)

Now that both numbers are expressed in twentieths, you can add the numerators: 8+15 = 23. So the answer can be reduced to 1 and 3/20. Which, if you break our your calculator and divide 23 by 20, you will find is OH's 1.15