adding and subtracting fractions
TRANSCRIPT
Adding and Subtracting Fractions
Criss-Cross Smiley Face Method
by Mr. Hoover
Click to begin
Adding and Subtracting Positive and Negative Numbers
Signs are the same: add the numbers and keep the sign.
• 2 + 3 = 5• -2 – 3 = -5• -2 + -3 = -5
Signs are opposite: subtract the numbers and take the sign of the larger number.
• 8 – 5 = 3 (8-5 is 3, and the sign of the larger number is positive)• 5 – 8 = -3 (8-5 is 3, and the sign of the larger number is negative)
Click to continue
Skills Review
Skills Review
Multiplying Positive and Negative Numbers
Signs are the same: the sign of the answer will be positive.
• 4 x 5 = 20• -4 x -5 = 20
Signs are opposite: the sign of the answer will be negative.
• 4 x -5 = -20• -4 x 5 = -20
Click to continue
Skills Review Adding, Subtracting, and Multiplying Positive and Negative Numbers
Click on the correct answer.
1. 5 + 2 = 01 2 3 4 5 6 8 9 10
-1 -2 -3 -4 -5 -6 -7 -8 -9 -10
7
Skills Review Adding, Subtracting, and Multiplying Positive and Negative Numbers
Click on the correct answer.
2. 5 – 2 01 2 74 5 6 8 9 10
-1 -2 -3 -4 -5 -6 -7 -8 -9 -10
3
Skills ReviewAdding, Subtracting, and Multiplying Positive and Negative Numbers
Click on the correct answer.
3. - 5 + 2 = 01 2 3 4 5 6 8 9 10
-1 -2
7
-4 -5 -6 -7 -8 -9 -10-3
Skills ReviewAdding, Subtracting, and Multiplying Positive and Negative Numbers
Click on the correct answer.
4. - 5 – 2 = 01 2 74 5 6 8 9 10
-1 -2 -3 -4 -5 -6
3
-8 -9 -10-7
You are correct!
Go on to the next question.
You are correct!
Go on to the next question.
You are correct!
Go on to the next question.
You are correct!
Move on to the next section.
Criss-Cross Smiley Face Method
Click to continue
2 + 3 = 5 4
Step 1: Criss – multiply 2 x 4 and bring down + sign
Step 2: Cross – multiply 3 x 5
Step 3: Smiley Face – multiply 5 x 4Step 4: Solve and simplify if needed. Leave fraction as an improper fraction.
2 x 4
8 + 20 5 x 4
3 x 5
15 23 = 20
Criss-Cross Smiley Face Method
Click to continue
1 - 2 = 6 3
Step 1: Criss – multiply 1 x 3 and bring down - sign
Step 2: Cross – multiply 2 x 6
Step 3: Smiley Face – multiply 6 x 3Step 4: Solve and simplify if needed. Leave fraction as an improper fraction.
1 x 3
3 - 18 6 x 3
2 x 6
12 -9 = = 18
-1
2
Practice
Click on the correct answer.Leave fraction as an improper fraction.
1 + 3 = 5 4
OK, let’s practice what we just learned.
= ?
?
?
?
49
420
199
1920
Practice
Click on the correct answer.Leave fraction as an improper fraction.
2 - 2 = 3 5
= ?
?
?
?
015
4 15
0-2
-415
Practice
Click on the correct answer. Leave fraction as an improper fraction.
6 + 4 = 7 3
= ?
?
?
?
2421
4621
1 1
2410
Practice
Click on the correct answer.Leave fraction as an improper fraction.
7 - 1 = 5 6
= ?
?
?
?
6 11
47 11
37 30
1 5
You are correct!
Go on to the next question.
You are correct!
Go on to the next question.
You are correct!
Go on to the next question.
You are correct! Congratulations!
You have completed the last question!
THE ENDTHE END
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