So if you want both denominators to be 4 in your example, you times both by 2.

1 × 2 = 2
2 × 2 = 4

Now your example is:

2/4 + 2/4

and you can reduce that down, ’cause 4 ain’t the lowest common denominator, is it?

1/2 + 1/2 = 2/2 or 1

That make sense? You just gotta figure out what you multiply the denominator by to get the LCD. Then multiply the numerator by the same thing.

Start off by askin’ yourself 4 questions:

1. Are both numbers in the fraction even?

If they are, you can usually split them in half to reduce. Like 2/4 can be cut down to 1/2. 12/16 to 6/8. 140/354 to 70/177. It don’t matter how big the number is, if it’s even, it can be split in half.

2. Is there a 5 or a 0 at the end of both numbers?

If there’s a 5 or a 0, you can reduce it down by 5. Like 5/15 can be reduced to 1/3. 20/65 to 4/13. 85/100 to 17/20.

3. Do all the digits in each number add up to 3, 6 or 9? (if all the numbers add up to a double digit number, add those up too.)

Like if you got 21, you can add 2 + 1 to equal 3. That means it’s divisible by 3. 12/45 = 4/15. 60/132 = 20/44 (and those are even, so you can reduce it down again to 10/22, and then to 5/11 again.)

4. Is it divisible by 7 or 13?

If it don’t got an even number, a 5 or a 0, or if the numbers don’t add up to 3, 6 or 9, then it’s most likely reduced as far as it can go. Double check to make sure both numbers aren’t reducible by either 7 or 13 though, since they don’t follow those rules. So like 21/35 = 3/5 ’cause both are divisible by 7. 78/143 = 6/11 ’cause both are divisible by 13.

Just remember to keep checkin’ through all four of these rules every time you reduce and you should be pretty good.

Did that help you out, Christina?