my daughter has a fraction problem. 1 2/5 - 3/4.

Question

she knows how to do it but winds up getting a negative.

Answer 1

I believe the answer 13/20. Start by changing 1 and 2/5 into an improper fraction. To make an improper fraction multiply the denominator by the whole number then add the numerator. So in our problem we would have, 1*5=5 5+2=7 Then, make 7 the numerator and keep the original denominator 5. The new problem would be 7/5- 3/4. Now find the common denominator. We can multiply 5*4 and 4*5 to get the new denominator, 20. Then we need to multiply the numerators by the same number we used to multiply the denominators. We multiplied 5 by 4 so we'll multiply 7 by 4 to get our new numerator which is 28. So, our first fraction is 28/20. Now lets' look at the second fraction. Since we multiplied 4 by 5, we'll multiply 3 by 5 which gives us 15. Now our problem is 28/20-15/20. 28-15=13 and our denominator is 20. Our answer is 13/20.

Answer 2

For this particular problem, I would convert each fraction into a decimal (using this method is not always beneficial, but because of the simplicity of the fractions, converting into decimals will provide for a faster means to the solution).

 

1 2/5 = 1 + .4 - we get 1.4 because 5 goes into 100 20 times and we multiply 2 by twenty to get 40. After obtaining 40, we need to convert into a decimal by dividing by 100, hence .4. Then we add the 1 to .4 to get 1.4.

 

3/4 = .75 - we get .75 because 4 goes into 100 25 times and we multiply 3 by 25 to get 75. After obtaining 75, we need to convert into a decimal by dividing by 100, hence .75.

 

Now we subtract .75 from 1.4 to get .65. 

 

We divide 65 by 5 to get 13 and then divide 100 by 5 to get 20.

 

So our answer is 13/20 or .65 as a decimal.

Answer 3

1 2/5 would need to be turned into an improper fraction. So,

1 2/5 would be 7/5 then,

7/5-3/4 and to solve this you would need to get A common denominator which 

in this case would be 20. So you final problem will be

(28/20)-(15/20)

=13/20