Quick solutions to this

Karen,

The base assumption that we work with is that if x divisible by 4 and y is divisible by 4 then x-y is divisible by 4.

In our case we have:

x = j-2 is divisible by 4
y = k - 5 is divisible by 4

x - y = j -2 -(k-5) = j - 2 - k + 5 = (j-k) + 3 is divisible by 4.

Now we just need to check each case:

A) j - k = 43 => 43 + 3 = 46 is NOT divisible by 4
b) j - k = 33 => 33 + 3 = 36 is divisible by 4
c) j - k = 21 => 21 + 3 = 24 is divisible by 4
d) j - k = 13 => 13 + 3 = 16 is divisible by 4
e) j - k = 5 => 5 + 3 = 8 is divisible by 4.

The obvious answer is A

Regards,
Mihaela

I really like the approach by Mixaela. You'll just have to prove to yourself that subtracting two multiples of 4 leaves a difference that is still a multiple of 4.

You can either know this to be true or you can prove it to yourself with a quick example on test day, i.e. 24-16=8, etc.