Bloopers
Multiplication
Division and the Standard Algorithm
Division and Models
Division and Common Denominators
100
What is the Mistake in this fractional computation?
5/12 = 15/24
Then numerator (x3) and denominator (x2) are not being multiplied by the same number. It could be 10/24, 15/36, or an infinite amount of other fractions if multiplied by another factor.
100
5/12*6/7 = ???
The correct answer is 5/14.
100
2/5 divide 3/7=???
The correct answer is 14/15.
100
Draw a model:
2/3 divide 1/4
See diagram
100
9/12 divide 3/12
The correct answer is 9/3 = 3
200
Find the Blooper! (and the correct answer)
3/7*4/7=12/7=1 5/12
They did not multiply the denominators straight across. They kept the denominators. The answer should be 12/49.
200
2 3/4*8/11=???
The answer is 2.
200
5 3/9 divide 12 = ???
The correct answer is 4/9
200
Draw a Model:
4/5 divide 1/3
See diagram
200
25/78 divide 6/78
The correct answer is 25/6 or 4 1/6
300
What is wrong? Find the right answer.
2/3 divide 5/7 = 3/2 *5/7=15/14=1 1/14
When dividing two fractions, find the reciprocal of the SECOND fraction, not the first one.
It should be 2/3 x 7/5 = 14/15.
300
3 1/3*6 1/2=???
The correct answer is 21 2/3.
300
7 1/2 divide 15/22 = ???
The correct answer is 11.
300
Draw a Model.
1/2 divide 1/5
See diag
ram.
300
32/40 divide 36/40
The correct answer is 32/36 = 8/9
400
Find the BLOOPER and the solution.
4/5*2/3=4/5*3/2=12/10=6/5=1 1/5
When multiplying fractions, just multiply straight across! 4/5 x 2/3 = 8/15
400
3 3/6*3 5/9 = ???
The correct answer is 112/9 or 12 4/9
400
30 divide 8 4/7 = ???
The correct answer is 7/2 or 3 1/2
400
Draw a Model:
2/5 divide 1/2
See dia
gram.
400
3/4 divide 18/20
The correct answer is 15/20 divided by 18/20 = 15/18 = 5/6
500
12/18 divide 2 1/2=12/18*5/2=60/36=5/3=1 2/3
When dividing by a mixed number, you need to convert it to an improper fraction and then find its reciprocal before multiplying. The correct answer should be 12/18 x 2/5 = 24/90 = 12/45.
500
24/36*15/48*72/75=???
The correct answer is 1/5
500
3 9/10 divide 1 17/35 = ???
The correct answer is 21/8 or 2 5/8
500
Draw a Model:
1/3 divide 3/4
See diagram.
500
7/8 divide 5/6
The correct answer is 21/24 divided by 20/24 which is 21 divided by 20 which is 21/20 or 1 1/20.