229k views
4 votes
Use compatible numbers to find two estimates
396/42

User JkShaw
by
7.8k points

1 Answer

1 vote

One estimate is 10 because

  • 396 is close to 400
  • 42 is close to 40

So 396/42 is close to 400/40 = 10

Using a calculator or long division shows that 396/42 = 9.43 approximately which isn't too far from 10.

----------------------------------------------

Another estimate is 8 because

  • 396 is close to 400
  • 42 rounds up to 50, when rounding up to the nearest tens

So 396/42 is somewhat close to 400/50 = 8

In some cases, dividing by 50 is easier than 40, but I think it's better to stick to the first estimate because it's closer but also because 400 and 40 can easily be divided mentally.

User Alphonse Prakash
by
8.3k points

Related questions

asked Sep 28, 2017 11.3k views
Kurious asked Sep 28, 2017
by Kurious
7.4k points
2 answers
1 vote
11.3k views
asked Sep 13, 2017 51.8k views
Simoes asked Sep 13, 2017
by Simoes
8.8k points
1 answer
0 votes
51.8k views
1 answer
2 votes
77.1k views