Dividing Fractions
This is the rule you use when dividing fractions.
What is multiply by the reciprocal (keep-change-flip)?
A student solves
3/4 divided by a 1/2
by multiplying 3/4 x 1/2
What mistake did the student make?
What is they forgot to flip the second fraction (use the reciprocal)?
A ribbon is 2 yards long. Each piece needs 1/2 yard.
How many pieces can be cut?
What is 4 pieces?
A student solved:
4.5 + 2.35 = 6.80
What is the correct answer?
What is 6.85?
Solve:
3/4 divided by a 1/2
What is 1 1/2
A student solves
1 1/2 divided by 3/4
by writing 1/2 divided by 3/4
What mistake did they make?
What is they ignored the whole number instead of converting the mixed number to an improper fraction?
A baker uses 2/3 cup of sugar for each batch of cookies.
If she has 4 cups of sugar, how many batches can she make?
What is 6 batches?
A recipe uses 3/4 cup of sugar per batch. You have 2 cups of sugar.
How many batches can you make?
What is 2 2/3 batches?
A student solves
2/3 divided by 4/5
by flipping both fractions.
What mistake did they make?
What is they should only flip the second fraction (the divisor)?
A rope is 3 meters long. Each jump rope needs 3/4 meter.
How many jump ropes can be made?
What is 4 jump ropes?
1 1/2 divided by 3/4
2
A student says
1/2 divided by 1/4 = 1/8.
What mistake did they make?
What is they multiplied instead of multiplying by the reciprocal?
A student drinks 3/4 liter of water each day.
How much water does the student drink in 6 days?
What is 4 1/2 liters?
A ribbon is 3 1/2 yards long. Each piece needs 5/8 yard.
How many pieces can be cut?
What is 5 3/5 pieces?
A student solves this problem:
A 3-cup container is filled with servings of 3/4 cup each.
They multiply 3 x 3/4.
What mistake did they make?
What is they should divide because the problem asks how many groups fit into the total?
Each small pizza uses 2/3 pound of cheese.
If a restaurant makes 9 pizzas, how much cheese is needed?
What is 6 pounds?