What is a easy way to add fractions? with or without a common demoninater.?

Question

please i suck at fractions and its for hw

Answer 1

You cannot add fractions without a common denominator. If you are asked to add 2 fractions, say 1/2 and 1/3, you have to find a number that 2 and 3 will both divide into. In this case, the lowest number (known as the LCD) would be 6. 6 divided by 2 is 3, so that would be 3/6. 6 divided by 3 is 2, so that would be  2/6 3/6 +2/6 =5/6.

If the fraction has a numerator bigger than 1, you have to multiply that as well. Say 3/4 + 2/3.  LCD would be 12.

12 /4 =3. 3*3 =9   12/3 =4 4*2=8 9/12 +8/12 = 17/12 =1 5/12.

Hope this helps.

Answer 2

5/12 + 7/18

1). Find the LCD. In this case it's 36 because 12 and 18 go evenly into 36, replace both denominators with 36

2). Divide. 36/12= 3  36/18= 2

3). Multiply 3 and 5 = 15 & 7 and 2 = 14

4). Replace the numerator with the product of 3 and 5 & 7 and 2...   15/36 + 14/36.

5). Solve 15/36 + 14/36, add 15 and 14= 29/36 since it's in lowest terms you can't reduce it further.

7/8 + 5/8

1). Add 7 & 5 = 12/8

2). Simplify (If nessasary) 12/8 =3/2 = 1.5

The way to find a common denominator is to multiply both denominators.

E.G. 5/6 + 2/4

Multiply 6 & 4 = 24

So 24 is going to be the denominator for both fractions.

Next the 5 in 5/6 has to be multiplied by 4 (Cross multiply) 20/24 <== That's your first complete fraction, now for the next one.

The 2 in 2/4 has to be multiplied by 6 = 12/24

12/24 <== That's your second fraction now add them

20/24 + 12/24 = 32/24 = 8/6 = 4/3 = 1.33333...

Hope this helped!! :]

Answer 3

You need to have a common denominator otherwise you won't be adding the same thing.

Try this example       2/5 + 3/8

1) First thing is to find a common denominator. Look at the bottom number and find a number that they both will go into. [Go through your times tables until you find a common number]. In this case the common denominator is 40

2) You can't just put 2/40 as this is not the same as 2/5. You need to multiply the top number by whatever you did to the bottom number.

So in order to get to 40 you needed to multiply 5 by 8. So now multiply the top number by 8 as well = 16

Your 2/5 fraction is now 16/40

3) Do the same with the other fraction. To get to 40 you needed to multiply the 8 by 5, so do the same to the top number [3 x 5 = 15] So your second fraction is now 15/40

4) You now have both fractions with a common denominator and you can now add them together 16/40 + 15/40 = 31/40

Hope this helps