Question

A recipe calls for 3/4 cup of butter. Angie wants to triple the recipe, but she has only 1 5/8.

Answer 1

Let's start out by tripling the original recipe to see how much butter Angie needs.

$\frac{3}{4} * 3 = total$
$\frac{3* 3}{4} = total$
$\frac{9}{4} = total$
$2 \frac{1}{4} = total$

So we need $2 \frac{1}{4}$ cups of butter, but Angie only has $1 \frac{5}{8}$. Let's subtract what Angie has from the total to see how much more she needs.

$2 \frac{1}{4} - 1\frac{5}{8} = n$
$\frac{9}{4} - \frac{13}{8} = n$
we will need the least common denominator for both fractions
$\frac{2}{2} *(\frac{9}{4}) - \frac{13}{8} = n$
$\frac{18}{8} - \frac{13}{8} = n$
$\frac{5}{8} = n$

So Angie need $\frac{5}{8}$ cups more of butter for the recipe.