That's N

That's 2N

That's 2N + 7

That's 

That says 

That's because you put the remainder over the divisor 
when you finish dividing. The divisor is 40 because that's
what we divided by.

We change the mixed number to an improper fraction 

Now we have this equation:



We multiply both sides by 40, and get: 

2N + 7 = 113

We subtract 7 from both sides:

    2N = 106

We divide both sides by 2

    N = 53

-------

Now we check

That's 53

That's 106

That's 106 + 7 = 113

That's this division

     2
40)113
    80
    33

It checks.

Edwin