Why 69 though????????????????????????
First off, let's convert the decimal to a fraction, notice, we have two decimals, so we'll use in the denominator, a 1 with two zeros then, two decimals, two zeros, thus

now, we know then the ratio dimensions for the new photograph,

S={ 11 12 13 14 15 16 17 18
21 22 23 24 25 26 27 28
31 32 33 34 35 36 37 38
41 42 43 44 45 46 47 48...
.......}
P(e)=(1+2+3+4+5+6)/64
=21/64=0.328(B)
A example of a Proper fraction is D =3/4
I'm guessing you meant the sum of a number AND 6? If so:
x+6=y or just x+6
x is a variable for "a number" and you add 6 to it. The y on the other side of the equals sign is because the sum (number you get when adding) is unknown due to the value of the x variable being unknown.