Transcript Subtracting Mixed Numbers with Renaming

Subtracting Mixed Numbers
with Renaming
Group Members
Mr. Pulley
Step 1
• Write the problem vertically.
5½
- 2¾
_________
Step 2
• Find the LCD for each
denominator.
Rename ½ to 2/4 and
¾ to ¾.
5½
5 2/4
- 2¾
-2¾
______ ______
Find the LCD of 2 and
4.
2 = 2, 4, 6
4 = 4, 8, 12
The LCD = 4
Step 3
• Can you subtract the numerators the way
they are now?
• NO!
• Rename in order to subtract.
• Borrow from the 5---make it a 4.
• Take away 1 from the
whole number 5, and add
1 whole to 2/4.
• How do you do this?
What is your
denominator? 4
• What is one whole of 4?
4/4=1 whole
• Rename 2/4 to 6/4
• 5 2/4
-2¾
_______
4 2/4
-2¾
_______
• 4 2/4 + 4/4= 4 6/4
-2 ¾
-2¾
_______
_______
Step 4
• First subtract the numerators and then you
can subtract the whole numbers.
-
4 6/4
2¾
Notice: the bottom mixed number stays the same
______________
2¾
• What is the difference? 2 ¾
Your Turn!
•
Solve the following word problem using
the steps you learned.
1. It usually takes Mr. Pulley 1 ¾ hours to
get to the beach. Due to Independence
Day traffic, this summer it took 3 1/3
hours. How much longer did it take this
summer?