Math 1

Question 1

Greatest Common Factor

Answer 1

Find prime factorizations of both numbers. Multiply each prime # the maximum number of times it occurs in BOTH factorizations

Question 2

Least Common Multiple

Answer 2

Find prime factorizations of both numbers. Multiply each prime # the maximum number of times it occurs in EITHER factorization.

Question 3

Even number raised to any exponent (e.g. 4^2)

Answer 3

Even

Question 4

Odd number raised to any exponent (e.g. 3^2)

Answer 4

Odd

Question 5

Compare size of fractions (e.g. 5/6 vs. 7/9)

Answer 5

Cross-multiply and compare resulting numbers.

Question 6

Convert mixed number to improper fraction (e.g. 5 and 3/4)

Answer 6

[(5*4) + 3] /4

Question 7

Percent increase

Answer 7

(New-Old) / Old

Question 8

Percent decrease

Answer 8

(Old-New) / Old

Question 9

Ratio of women to men is 4:6. If 32 people in room, find # of women

Answer 9

32(#women/#total) = 32(4/10)

Question 10

A does task in 3 hours. B does same task in 2 hr. Together, how long would it take them?

Answer 10

1/a + 1/b = 1/T Where T=total time taken. 1/3 + 1/2 = 5/6. Takes them 6/5 hours together.

Question 11

Weighted average: Bowler A has average score of 100 over 4 games. Bowler B has average score of 200 over 16 games. Find average of both bowlers over all games.

Answer 11

Average of both is [(100)(4)+(200)(16)] \ (16+4)

Question 12

Combinations

Answer 12

How many unordered subgroups can be formed from a larger group? Formula: n! / k!(n-k)!

Question 13

Sum of interior angles of a polygon

Answer 13

180*n where n is the number of triangles that the polygon can be divided into by drawing diagonals.

Question 14

Isosceles triangle

Answer 14

2 equal sides opposite 2 equal angles.

Question 15

Measure of an exterior angle of a triangle

Answer 15

=sum of measure of two remote interior angles.

Question 16

Special right triangles

Answer 16

3 4 5 ; 5 12 13

Question 17

Side ratios for 30-60-90 triangle

Answer 17

x-x(root 3)-2x

Question 18

Side ratios for 45-45-90 triangle

Answer 18

x-x-x(root 2)

Question 19

Area of a parallelogram

Answer 19

bh

Question 20

Lateral surface of a cylinder (pipe surface, not circular faces)

Answer 20

=2 pi r h

Question 21

Volume of cylinder

Answer 21

(Area base) (height), or h pi r^2

Question 22

Divisible by 2 if

Answer 22

Last digit is divisible by 2

Question 23

Divisible by 3 if

Answer 23

Integers add up to a multiple of 3

Question 24

Divisible by 4 if

Answer 24

Last two digits are a multiple of 4

Question 25

Divisible by 5 if

Answer 25

Last digit is 0 or 5

Question 26

Divisible by 6 if

Answer 26

Divisible by both 2 and 3

Question 27

Divisible by 9 if

Answer 27

Digits add up to a multiple of 9