The factors of 64 are [1, 2, 4, 8, 16, 32, 64] and the factors of 36 are [1, 2, 3, 4, 6, 9, 12, 18, 36]. They share 3 factors [1, 2, 4] making 4 the greatest factor 64 and 36 have in common.

A prime number is an integer greater than 1 that has no factors other than 1 and itself. Examples of prime numbers include 2, 3, 5, 7, and 11.

To find the average of these 4 numbers add them together then divide by 4:

\( \frac{15 + 11 + 14 + 12}{4} \) = \( \frac{52}{4} \) = 13

The absolute value is the positive magnitude of a particular number or variable and is indicated by two vertical lines: \(\left|-5\right| = 5\). In the case of a variable absolute value (\(\left|a\right| = 5\)) the value of a can be either positive or negative (a = -5 or a = 5).

To divide fractions, invert the second fraction and then multiply:

\( \frac{3}{8} \) ÷ \( \frac{3}{7} \) = \( \frac{3}{8} \) x \( \frac{7}{3} \)

To multiply fractions, multiply the numerators together and then multiply the denominators together:

\( \frac{3}{8} \) x \( \frac{7}{3} \) = \( \frac{3 x 7}{8 x 3} \) = \( \frac{21}{24} \) = \(\frac{7}{8}\)