Directions : Please come in and get your journal. On your next blank page, write today’s date on the top line. Title this page ~ Adding and Subtracting Fractions . Below the date, write the Challenge Question . .
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Directions: Please come in and get your journal. On your next blank page, write today’s date on the top line. Title this page ~ Adding and Subtracting Fractions.
Below the date, write the Challenge Question.
Challenge Question: How does knowing parttowhole relationships help you add and subtract fractions?
Warmup (independent, level 0 noise):
Please complete this in your journal below the CQ
Add or Subtract the following Fractions:
+

1 
A fraction is an ordered pair of whole numbers, the 1st one is usually written on top of the other, such as ½ or ¾ .
numerator
denominator
The denominator tells us how many congruent pieces the whole is divided into, thus this number cannot be 0.
The numerator tells us how many such pieces are being considered.
denominator to add
these fractions.
+
Count by 2's
2, 4, 6, 8, 10, 12, 14, 16, 18, 20
Count by 7's
7, 14, 21, 28, 35…
2, 4, 6, 8, 10, 12, 14, 16, 18, 20
Count by 7's
7, 14, 21, 28, 35…
The first number IN COMMON
that appears on both lists
becomes the common denominator
denominator to add
these fractions.
+
Count by 7's
7, 14, 21, 28, 35, 42, 49, 56, 63
Count by 8's
8, 16, 24, 32, 40, 48, 56, 64, 72
Identify the common denominator.
1 ½  ¼
ANSWER: 4
Since ¼ already has a denominator of 4 you don’t need to change it.
But ½ needs to be converted to 4’ths.
Step #1 Step #22 x 2 = 4
4 x 4 = 16
The problem now reads like this:
3 4/16 – 15/16
Normally you would now subtract. The problem is that 4 – 15 would be a negative number. We can’t have that!
THUS, BORROWING IS NEEDED!
Oops! What’s this?3 4/16 – 15/16
2 + 1 4/16 = 3 4/16?
2 + 1 4/16 needs to be changed a bit before we can subtract from it.
Lets take 1 4/16 and “fix” it.
Because 16 is the common denominator we need to write 1 in 16ths.
We can write 1 as:
2/2 = 1
3/3 = 1
4/4 = 1
And so forth up to:
16\16 = 1
SO NOW:
16 + 4 = 20
16 16 16
The tricky part