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

\( \frac{4}{5} \) x \( \frac{1}{9} \) = \( \frac{4 x 1}{5 x 9} \) = \( \frac{4}{45} \) = \(\frac{4}{45}\)

The ratio of football cards to baseball cards is 9:2 and the ratio of baseball cards to basketball cards is 9:1. To solve this problem, we need the baseball card side of each ratio to be equal so we need to rewrite the ratios in terms of a common number of baseball cards. (Think of this like finding the common denominator when adding fractions.) The ratio of football to baseball cards can also be written as 81:18 and the ratio of baseball cards to basketball cards as 18:2. So, the ratio of football cards to basketball cards is football:baseball, baseball:basketball or 81:18, 18:2 which reduces to 81:2.

The amount of flour you need is (2\(\frac{7}{8}\) - 1) cups. Rewrite the quantities so they share a common denominator and subtract:

(\( \frac{23}{8} \) - \( \frac{8}{8} \)) cups
\( \frac{15}{8} \) cups
1\(\frac{7}{8}\) cups

You have 31 out of the total of 450 raffle tickets sold so you have a (\( \frac{31}{450} \)) x 100 = \( \frac{31 \times 100}{450} \) = \( \frac{3100}{450} \) = 7% chance to win the raffle.