Colin buys a box of pasta that contains 8 2/3 cups of pasta. He uses 2 1/2 cups to make dinner.

How much pasta is left?

Enter your answer in the box as a mixed number in simplest form.

1 answer

To find out how much pasta Colin has left after using some for dinner, we need to subtract the amount he used from the total amount he had.

Colin starts with: \[ 8 \frac{2}{3} \text{ cups} \]

He uses: \[ 2 \frac{1}{2} \text{ cups} \]

First, we convert both mixed numbers to improper fractions.

  1. Convert \( 8 \frac{2}{3} \):

    \[ 8 \frac{2}{3} = 8 \times 3 + 2 = 24 + 2 = 26 \quad \text{(numerator)} \] So, \[ 8 \frac{2}{3} = \frac{26}{3} \]

  2. Convert \( 2 \frac{1}{2} \):

    \[ 2 \frac{1}{2} = 2 \times 2 + 1 = 4 + 1 = 5 \quad \text{(numerator)} \] So, \[ 2 \frac{1}{2} = \frac{5}{2} \]

Next, we need to subtract \( \frac{5}{2} \) from \( \frac{26}{3} \). To do this, we need a common denominator. The least common multiple (LCM) of 3 and 2 is 6.

We convert both fractions:

  1. Convert \( \frac{26}{3} \) to a denominator of 6:

    \[ \frac{26}{3} = \frac{26 \times 2}{3 \times 2} = \frac{52}{6} \]

  2. Convert \( \frac{5}{2} \) to a denominator of 6:

    \[ \frac{5}{2} = \frac{5 \times 3}{2 \times 3} = \frac{15}{6} \]

Now we can subtract the two fractions:

\[ \frac{52}{6} - \frac{15}{6} = \frac{52 - 15}{6} = \frac{37}{6} \]

Now, we convert \( \frac{37}{6} \) back to a mixed number:

  1. Divide 37 by 6. The quotient is 6 and the remainder is 1.

So, \[ \frac{37}{6} = 6 \frac{1}{6} \]

Thus, the amount of pasta Colin has left is:

\[ \boxed{6 \frac{1}{6}} \]