The factors of 80 are [1, 2, 4, 5, 8, 10, 16, 20, 40, 80] and the factors of 20 are [1, 2, 4, 5, 10, 20]. They share 6 factors [1, 2, 4, 5, 10, 20] making 20 the greatest factor 80 and 20 have in common.

A factorial is the product of an integer and all the positive integers below it. To solve a fraction featuring factorials, expand the factorials and cancel out like numbers:

\( \frac{2!}{6!} \)
\( \frac{2 \times 1}{6 \times 5 \times 4 \times 3 \times 2 \times 1} \)
\( \frac{1}{6 \times 5 \times 4 \times 3} \)
\( \frac{1}{360} \)

Christine scored 97% on the test meaning she earned 97% of the possible points on the test. There were 360 possible points on the test so she earned 360 x 0.97 = 348 points. Each question is worth 4 points so she got \( \frac{348}{4} \) = 87 questions right.

A rational number (or fraction) is represented as a ratio between two integers, a and b, and has the form \({a \over b}\) where a is the numerator and b is the denominator. An improper fraction (\({5 \over 3} \)) has a numerator with a greater absolute value than the denominator and can be converted into a mixed number (\(1 {2 \over 3} \)) which has a whole number part and a fractional part.

A rational number (or fraction) is represented as a ratio between two integers, a and b, and has the form \({a \over b}\) where a is the numerator and b is the denominator. An improper fraction (\({5 \over 3} \)) has a numerator with a greater absolute value than the denominator and can be converted into a mixed number (\(1 {2 \over 3} \)) which has a whole number part and a fractional part.