3 5/7+ 7 1/2

1 answer

To add the two mixed numbers \(3 \frac{5}{7}\) and \(7 \frac{1}{2}\), you can follow these steps:

  1. Convert the mixed numbers into improper fractions.
  2. Find a common denominator.
  3. Add the fractions.
  4. Convert back to a mixed number if necessary.

Step 1: Convert to improper fractions

  • For \(3 \frac{5}{7}\): \[ 3 \frac{5}{7} = \frac{3 \times 7 + 5}{7} = \frac{21 + 5}{7} = \frac{26}{7} \]

  • For \(7 \frac{1}{2}\): \[ 7 \frac{1}{2} = \frac{7 \times 2 + 1}{2} = \frac{14 + 1}{2} = \frac{15}{2} \]

Step 2: Find a common denominator

The denominators are 7 and 2. The least common multiple (LCM) of 7 and 2 is 14.

Convert both fractions to have a denominator of 14:

  • For \(\frac{26}{7}\): \[ \frac{26}{7} = \frac{26 \times 2}{7 \times 2} = \frac{52}{14} \]

  • For \(\frac{15}{2}\): \[ \frac{15}{2} = \frac{15 \times 7}{2 \times 7} = \frac{105}{14} \]

Step 3: Add the fractions

Now that we have a common denominator: \[ \frac{52}{14} + \frac{105}{14} = \frac{52 + 105}{14} = \frac{157}{14} \]

Step 4: Convert back to a mixed number

To convert \(\frac{157}{14}\) back to a mixed number, divide 157 by 14:

  • 14 goes into 157 eleven times (since \(14 \times 11 = 154\)).
  • The remainder is \(157 - 154 = 3\).

So, \(\frac{157}{14} = 11 \frac{3}{14}\).

Final Answer

\[ 3 \frac{5}{7} + 7 \frac{1}{2} = 11 \frac{3}{14} \]