When you divide a whole number by a decimal less than 1, the quotient is greater than the whole number. why ?

Yes, the number is greater, but there is an explanation. You are dividing a whole number by a decimal less than 1, yes? That means, that the answer you get, when multiplied with the decimal less than 1, will equal 7. And a decimal less than one is really small, so to get the whole number that you are dividing, they will have to multiply with a large number to get that whole number.

Confusing, I know. Let me add an example. Say you're dividing 7 by 0.875. Once divided, your answer is 8. Because 0.875 × 8 equals to 7. The smaller-than-1 decimal will need a larger number to get  to the number it is dividing.

7 ÷ 0.875 = 8.

The calculator should help if you want to back this up. Does this make sense, or am I making things more complicated?

It should be c i think.