A pizza had 9/10 left before Lucas ate 4/5 of the pizza. How much pizza is left over? of a pizza

Step-by-step explanation:

always try to bring fractions you need to compare to the same denominator (bottom number).

we have 9/10 of the pizza left.

then 4/5 if the pizza are eaten.

how to compare 9/10 with 4/5 ?

by bringing 4/5 also to a fraction of 10ths.

what do I need to multiply 5 with to get 10 ?

right, 2.

since we don't want to change the overall value of the original fraction, we need to multiply both levels (numerator and denominator) by that same factor :

4/5 × 2/2 = 8/10

aha !

that we can compare with 9/10.

so, when Lucas ate 4/5 (= 8/10) of the pizza, when there was originally 9/10 left, then we have 1/10 of the pizza left.