add: 1/2 + 3/4 + 2/5 (please explain your answer)?

Question

thanks :)

Answer 1

You need to find a commen number for the bottom. So go with 20-multipy each fraction by what is needed to get to 20. So-
10(1/2)+5(3/4)+4(2/5)=
10/20 + 15/20 + 8/20 =
33/20 = 1 13/20

Answer 2

1/2 + 3/4 + 2/5= 1 and 13/20

You have to give them all a common denominator, which in this case is 20. So it would be:

1* 10/ 2*10 + 3* 5/ 4* 5 + 2* 4/ 5* 4=

10/20 + 15/20 + 8/ 20

Add the top numbers: 10+ 15+ 8= 33;


So, it would be 33/20 (20 is the common denominator), but that is an improper fraction, so u have to convert it to a proper fraction, which would be 1and 13/20.

Hope this helped.

Answer 3

Find the lowest common denominator (it's 20, can't remember how to explain how to find it exactly).

Multiply the top and bottom of each fraction by whatever number makes the bottom 20.

1/2 => 10/20; 3/4 =>15/20; 2/5 =>8/20.

Add the numerators together.

10 + 15 + 8 = 33

Put the denominator back on - 33/20.

So 33/20 is your answer - you may need to reduce/put into a decimal/whatever for the answer your teacher wants.

Answer 4

1/2 + 3/4 + 2/5

find a common denominator. can be found by finding the least common multiple (the denominator is the number on the bottom and the numerator is on top)

so your denominator is 20 since if you look at the multiples

2: 2,4,6,8,10,12,14,16,18,20
4: 4,8,12,16,20
5: 5,10,15,20

so 20 is the first number all denominators have in common.

then you have to multiply each numerator by the same number you multiply the original denominator to get 20.

2X10, 4X5, 5X4
numerators are:
1X10, 3X5, 2X4= 10,15,8
so the new fractions are:

10/20 + 15/20 + 8/20

next add the numerators together

10+15+8=33

so your final fraction is:

33/20 and neither of them have common factors so it can't be reduced but always be sure to check to make sure the answer is in lowest form (unless otherwise specified)

yay i love math!