Betty scored 80% on the test meaning she earned 80% of the possible points on the test. There were 240 possible points on the test so she earned 240 x 0.8 = 192 points. Each question is worth 3 points so she got \( \frac{192}{3} \) = 64 questions right.

A factor is a positive integer that divides evenly into a given number. For example, the factors of 8 are 1, 2, 4, and 8.

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

(\( \frac{23}{8} \) - \( \frac{7}{8} \)) cups
\( \frac{16}{8} \) cups
2 cups

Average speed in miles per hour is the number of miles traveled divided by the number of hours:

A number in scientific notation has the format 0.000 x 10^exponent. To convert to scientific notation, move the decimal point to the right or the left until the number is a decimal between 1 and 10. The exponent of the 10 is the number of places you moved the decimal point and is positive if you moved the decimal point to the left and negative if you moved it to the right:

0.000218 in scientific notation is 2.18 x 10^-4