Question

7 7/8 - 3 1/4 equals what

Answer 1

$7 \frac{7}{8} -3 \frac{1}{4} \\ \\ \frac{7 \times 8 + 7}{8} \\ \\ \frac{56+7}{8} - 3 \frac{1}{4} \\ \\ \frac{63}{8} -3 \frac{1}{4} \\ \\ \frac{63}{8} - \frac{3 \times 4 + 1}{4} \\ \\ \frac{63}{8} - \frac{12+1}{4} \\ \\ \frac{63}{8} - \frac{13}{4} \\ \\ LCD = 8 \\ \\ \frac{63}{8} - \frac{12 \times 2}{4 \times 2} \\ \\ \frac{63}{8} - \frac{26}{8} \\ \\ \frac{63 - 26}{8} \\ \\ \frac{37}{8} \\ \\ \frac4{5}{8} \\ \\ Answer: \fbox {4 5/8} \ or \ \fbox {4.625}$

Answer 2

The difference of 7 and 7/8 and 3 1/4 can be restated as the difference between 63/8 and 13/4. This is just a change from mixed numbers to improper fractions. 

We must now get a common denominator (the bottom part of a fraction). To get 8, we must multiply by 2 to the denominator of 13/4. Since we want this number to stay in the same value, we have to multiply the numerator by 2 as well (top part of the fraction). Therefore, we are getting the difference of 63/8 and 26/8. Doing this, we get (63-26)/8, so the answer is 37/8 = 4 5/8