Which choice shows the correct way to write a fraction multiplication problem as an addition. A. 6•1/3=1/6+1/6+1/6+1/6 b. 3•3/5=3/5+3/5+3/5+3/5 c. 2•2/5=5/2+5/2 d. 1•4/7=1/7+1/7+1/7+1/7

1 answer

To convert a fraction multiplication problem into an addition problem, you need to express the multiplication as repeated addition of the fractional part. In general, multiplying a whole number by a fraction \( a \cdot \frac{b}{c} \) can be rewritten as adding \( \frac{b}{c} \) a number of times equal to the whole number \( a \).

Let's look at each choice:

A. \( 6 \cdot \frac{1}{3} = \frac{1}{6} + \frac{1}{6} + \frac{1}{6} + \frac{1}{6} + \frac{1}{6} + \frac{1}{6} \)

  • Incorrect, as it should be \( \frac{1}{3} \) added six times.

B. \( 3 \cdot \frac{3}{5} = \frac{3}{5} + \frac{3}{5} + \frac{3}{5} \)

  • Correct, since it represents adding \( \frac{3}{5} \) three times.

C. \( 2 \cdot \frac{2}{5} = \frac{5}{2} + \frac{5}{2} \)

  • Incorrect, since it should be \( \frac{2}{5} \) added twice.

D. \( 1 \cdot \frac{4}{7} = \frac{1}{7} + \frac{1}{7} + \frac{1}{7} + \frac{1}{7} \)

  • Incorrect, it should just be \( \frac{4}{7} \) added once.

The correct answer is:

B. \( 3 \cdot \frac{3}{5} = \frac{3}{5} + \frac{3}{5} + \frac{3}{5} \)