Notice that the divisors 2,000, 200 and 20 are similar except for the number of zeros.
You can remove a zero from each dividend equal to the number of zeros in the divisor.
So 80,000 ÷ 2,000 is equivalent to 80 ÷ 2 = 40 ( I removed 3 zeros from each)
80,000 ÷ 200 is equivalent to 800 ÷ 2 = 400 (notice that I could only remove 2 zeros)
Finally 80,000 ÷ 20 only allows us to remove on zero --- 8,000 ÷ 2 = 4,000.
The smaller the divisor the greater the quotient (when dividing the same number - in this case 80,000)
