6.1 Dividing Fractions by

whole numbers

Grade 8 by Rhonda Friesen

What we already know about division…

• 6÷ 2=• We know that division is splitting up a number

into equal size groups. • How many groups of 2 are in 6?

Vocabulary for division • 6÷ 2=• 6 is the dividend (Total number)• 2 is the divisor (number of apples in each group)• 3 is the quotient (number of groups)

6÷ ½ = ?

• I have six apples. I am going to share my apples with some friends. If I give each friend ½ an apple, how many friends can I give apples?

• I have 5 pizzas. I am going to share my pizzas with some friends. If I give each friend 1/3 of the pizza, how many friends will get pizza?

Using a bar model • We have 6 cupcakes. We decide to put them

equally into 3 boxes. How many cupcakes will be in each box?

• 6÷ 3=

• Cupcakes

6 is 3 groups of

what number ?

If ½ a box of cupcakes can hold 6 cupcakes, how many cupcakes

can the box hold?• 6÷ ½ = ?• 6 is ½ of what number?

• Cupcakes

If 1/3 of a gas tank holds 5 liters of gas, how many liters does the gas

tank hold?• 5 is 1/3 of what number?• What is the equation?

Keith was preparing the course for a 3 mile bicycle race. He set up water stations every

¾ mile for the bicycle riders in the race. How many water stations did he set up?

• What is the equation ?• ___________________

Sabrina has 6 pizzas at her birthday party. If each person

can eat 2/3 of a pizza, how many people can she serve? • What is the equation? • ___________________

Dividing whole numbers and fractions without models…

• You know that..o 2÷ ¼ = how many groups of ¼ are in 2.

o 2÷ ¼ has the same answer as

When we are dividing by a fraction, we can get the same answer by multiplying by the

flip of the fraction.• 3÷ 1/5 =

Reciprocal• The flip of a fraction is called the reciprocal• The reciprocal of ½ is ________• The reciprocal of 1/3 is ______• The reciprocal of 1/6 is ______• The reciprocal of 2/3 is _______• The reciprocal of ¾ is ________• The reciprocal of 7/9 is _______

Aliyah has 6 sticks of butter. She needs 1/3 of a butter stick to make a dozen cookies.

How many dozens of cookies can she make? • How many groups of 1/3 are in 6? • There are ____ groups of 1/3 are in 6.• What is your equation? _________________• SOLVE:

• Sentence: _____________________________

What happens if the whole number is not at

the beginning of the equation?

Three students shared 2/3 of a cake equally. What fraction of the cake did each student

receive?• What is the equation? _______________• 2/3 is 3 groups of what number ?• My answer will be _____________than 2/3.

Kiah divided ¾ pounds of grapes equally with 2 children she was babysitting. What

fraction of the grapes did each child receive?

• Equation: _________________• ¾ is 2 groups of what number?