I think that jeremy should learn how to do his own math
Multiples of 8 are basically the result of counting by 8's. (Technically, multiples are a set of number which can be divided by a certain number without a remainder.)
The first 4 multiples of 8 are {

}.
Thing 1
A. You can set up a proportion by dividing how much of something there is by the original. (This probably doesn't make much sense but I hope you can understand it from the answer to the problem below!)
B.First, do 168/21 to see how many more times he put flour in.
168/21= 8
Then to find out the milk in the same proportion do the number (in this case 8) times the original of the thing you wan to find out.
8x9=72
72 tablespoons of milk are needed for 168 cups of flour in this adapted recipe.
Thing 2
24/36=8y
To solve any equation, you want to have letters on one side and numbers on the other, so...
-8 from both sides...
(24/36)-8=y
24/36=0.6
y=(0.6-8)
y=-7.4
Hope this helps :)
3^2 = 9
9/9 = 1
1 + 12 = 13
This is based on the Order of Operations.
Hope it helps! :D