612 is very close to 600 and 600 into 60 is 100
[tex]\frac{600}{60}=100[/tex]Also, we have 12 in front of 600 that makes it 612 and we know that 12 is not divisible by 60, and therefore, it will be the remainder.
Hence, the estimate of the quotient of 612 and 60 is 100
