Emilia bought 9/12 pound of sliced salami at the deli counter. which of the following decimals did the scale show?

0.25
0.34
0.7
0.75

To start this problem, what we need to do is try to simplify the fraction into one we might know already. The best way to go about doing this is to see if we can divide the top and bottom by any of the same numbers. 

We can divide 9 by 1, 3, and 9
We can divide 12 by 1, 3, 4, and 12

Looking back over the  numbers, we can see that both 9 and 12 are divisible by 3, so if we divide both of them by 3, we will get a new fraction! This fraction will be 3/4.

Our next step is to see if we know what 3/4 is. I know 1/4 is .25 because the coin called a quarter is 25 cents, so if I had 3 quarters, I would have 75 cents, so I know know that 9/12 = 3/4 = .75!

31 is prime. and it’s prime factorization is just 31.