In order to solve this, we must find out how many times 7 goes into 80. We can do this by either subtracting individual 7s from 80, or by adding 7s together until we cannot add another without going past 80.
For this answer, I will use the addition method.
7 + 7 = 14
14 + 7 = 21
21 + 7 = 28
28 + 7 = 35
35 + 7 = 42
42 + 7 = 49
49 + 7 = 56
56 + 7 = 63
63 + 7 = 70
70 + 7 = 77
From 77, we cannot add another 7 to it without going over 80, since 77 + 7 = 84.
So, let's count the sevens that we have added up so far, and when we do, we can see that there are 11 of them, adding up to 77.
So 7 goes into 80 11 times. Now, let's find the remainder...
To find the remainder, you just need to subtract the final added number from the number you are dividing from.
80 - 77 = 3
80 / 7 = 11, remainder 3
Hope that helped! =)