Determine two compatible numbers to use to estimate the quotient 5,071 62.
A. 4,800 and 60

B. 4,900 and 70

C. 5,000 and 60

D. 5,100 and 60

Question

Determine two compatible numbers to use to estimate the quotient 5,071  62. 
 A. 4,800 and 60  
 
 B. 4,900 and 70  
 
 C. 5,000 and 60  
 
 D. 5,100 and 60

anonymous · Answer

A is OK, but both of those numbers have been rounded down, so that's not ideal.
B is better in that one has been rounded down and the other up, but rounding 62 all the way to 70 is pretty high. It is easy to do the mental arithmetic on that one though.
C has the same problem as A, and those numbers aren't really very compatible.
D has well-rounded numbers, and they are compatible if you know your multiplication tables well enough.