Multiplication, Division, and Related Concepts (Inverse Operations, Factors, Multiples, Estimation, and Division Methods)

Notes

# INVERSE OPERATIONS Multiplication and division are inverse or opposite operations. This means you can check a multiplication activity by doing division and you can check a division activity by doing multiplication. For example: 24 x 2 = 48 therefore 48 ÷ 2 = 24 72 ÷ 8 = 9 therefore 9 x 8 = 72 # FAMILITIES A multiple is the answer which we get when we multiply two numbers together. For example: 4 x 5 = 20, so 20 is a multiple of both 4 and 5 10 x 2 = 20, so 20 is a multiple of both 10 and 2 We can find multiples using our times tables: For example: The first ten multiples of 3 are: 3; 6; 9; 12; 15; 18; 21; 24; 27; 30 The first six multiples of 7 are: 7; 14; 21; 28; 35; 42 # FACTORS Factors are numbers that divide into another number exactly. (Factors 'fit in') For example: Finding the factors of 24: 24÷1=24 and 24÷24=1, so 1 and 24 are factors of 24 24÷2=12 and 24÷12=2, so 2 and 12 are also factors of 24 24÷3=8 and 24÷8=3, so 3 and 8 are also factors of 24 24÷4=6 and 24÷6=4, so 6 and 4 are also factors of 24 Therefore all the factors of 24 are 1; 2; 3; 4; 6; 8; 12 and 24 Factors are shown in pairs. For example, as shown above, the factor pairs for 24 are: 1 and 24 2 and 12 3 and 8...