Download Multiplying Fractions with Cross Cancellation

Multiplying Fractions
with Cross Cancellation
Cross Cancellation - dividing a
numerator and a denominator by the
same number
Cross Cancellation
• Multiply 3 x 1
•
4 3
• Step 1. Look for the same number in
the numerator and denominator. 3 is
in the numerator and denominator.
• Step 2. Divide the numerator and
denominator by 3. Write the new
numerator and denominator.
• Step 3. Multiply the new numerator
and denominators.
• The Product of 3/4 times 1/3 is 1/4.
• Multiply. Use
cross
cancellation first.
• 1. 1/5 x 5/6
• 2. 3/8 x 1/3
• 3. 1/8 x 8/9
• 4. 4/5 x 3/4
Remember!
You can use cross cancellation even when you do
not see the same number in the numerator and
denominator. Look for the other common factor.
Example
Multiply 1 x 4
2 5
Step 1. Find a common factor of a numerator and
denominator. 2 and 4 have a common factor of 2.
Step 2. Divide the denominator 2 and the numerator 4 by
the common factor. Write the new numerator and
denominator.
Step 3. Multiply the new numerators and denominators.
Sometimes you can cross-cancel more than once.
You can cancel two times.
Step 1. Find common factors of the numerators and
denominators 3 and 15 have a common factor of 3, 6
and 10 have a common factor of 2.
Step 2. Divide the numerators and denominators by the
common factors. Write the new numbers.
Step 3. Multiply the new numerators and denominators.