Multiplicative Inverse
Multiplicative Inverse
Multiplicative Inverse: the product of a number and its multiplicative
inverse is 1. The multiplicative inverse is the reciprocal.
a 1
a =1
Example:
multiplicative inverse
8 The multiplicative inverse (reciprocal) of 8 is 1
8
8 1=1
8
What if a number was negative? What would the multiplicative inverse
be in order to have a product of 1?
Example: ­ 2
3
Engage New York: Module 3, Lesson 2
Multiplicative inverses have a product of 1. Fill in the center column of the table with the opposite of the given number or expression, then show the proof that they are opposites.
Expression
Opposite
Use the multiplicative inverse to write the corresponding
expression in standard form.
A. 12 ÷ 3
Proof of Opposite
3
5
B. 65 ÷ ­5
­2
­3/5
C. 6 ÷ 3
5
x
3x
D. 5x ÷ x
E. 12x ÷ 2x
1
Multiplicative Inverse
Use the multiplicative inverse to write the corresponding
expression in standard form. Then, evaluate the expression using the
value given for the variable in the original expression and when in
standard form. Do the answers match?
1
A. 8x ÷ 2; x = 4
B. 18w ÷ 6w; w = ­2
C. 24xy ÷ 6y; x = ­2, y = 3
2