Answer:
18
Explanation:
Divide the total weight of dough by the amount required for 1 pizza
20
÷ 1
( change mixed numbers to improper fractions )
=
÷

• leave first fraction , change ÷ to × , turn second fraction ' upside down '
=
×
( cancel 81 and 9 by 9 )
=
× 8 ( cancel 4 and 8 by 4 )
= 9 × 2
= 18 pizza's