Transcript 7th Grade Sept 3 add_subt_fractions

Adding & Subtracting Fractions
Teacher Notes:
• Use this presentation to teach the steps
for adding and subtracting fractions with
unlike denominators.
• It is assumed that students have a
thorough understanding of the process for
making equivalent fractions.
• CLICK HERE to view a demonstration with
opportunities for students to practice
making equivalent fractions.
Step 1: Find a
common
denominator
to add
these fractions.
Step 1: Find a
common
denominator
to add
these fractions.
2, 4, 6, 8, 10, 12, 14, 16, 18, 20
7, 14, 21, 28, 35…
x7
7
X7
x2
6
7 + 6 = 13
x2
13
Step 1: Find a
common
denominator
to add
these fractions.
7, 14, 21, 28, 35, 42, 49, 56, 63
5, 10, 15, 20, 25, 30, 35, 40, 45
x5
15
X5
x7
7
x7
15 + 7 = 22
22
Step 1: Find a
common
denominator
to add
these fractions.
7, 14, 21, 28, 35, 42, 49, 56, 63
8, 16, 24, 32, 40, 48, 56, 64, 72
x8
32
x8
x7
21
32 + 21 = 53
x7
53
Step 1: Find a
common
denominator
to add
these fractions.
5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55
11, 22, 33, 44, 55, 66, 77…
x5
15
x5
x 11
11
15 - 11 = 4
x 11
4
Try These
A
D
B
E
C
F
Answers On Next Slide
• Each click on the next slide
reveals an answer.
• Check your papers.
• If you discover an incorrect
answer, be able to explain
your mistake.
Try These
17
27
D
10
9
B
13
12
E
41
28
C
19
20
F
26
21
A