There might be some questions on the GED math test that require you to do multiple operations during a single step of the problem. In order to arrive at the correct answer you need to perform the operations in a certain order. The mnemonic device PEMDAS or “please excuse my dear Aunt Sally” is often used for this. Here’s what the initials stand for:
P: do parentheses first
E: do exponents second
M: do multiplication third
D: do division fourth
A: do addition fifth
S: do subtraction sixth
Here is an example:
PEMDAS. P, do whatever is in parentheses first, which is 9 + 7.
PEMDAS. E, do whatever exponents there are. We have 16² = 256
PEMDAS. M, is there any multiplication? Yes, 18 times 8 = 144.
PEMDAS. D, do any division. 256 over 78 is a division problem. 256 divided by 8 is 32.
PEMDAS. A, do addition. 32 + 36 = 68
PEMDAS. S, finally do the subtraction.