Explanation:
At each step, the product of the quotient digit and the divisor is subtracted from the dividend. This gives you the new dividend.
When the quotient digit is 7, the product of 7 and 5 is subtracted from the dividend. The dividend at that point is 35, so you have 35 - 35 = 0. The 0 is the next dividend. Among other things, that tells you you're done. (Any additional quotient digits will be zero.)
