Estimate is not a rounding problem. We are not supposed to know the exact answer when we do the estimates.
What is important with estimates is HOW you estimate, not just the final number.
Anybody with a calculator can get the exact value. The exercise is to estimate when we do NOT have a calculator (or cell phone!).
I don't know how you got -4000 for -72 x 57. I would have done -70*60=-4200,
For -92 x (-41), I would have got
-90*-40=3600
If you want more accuracy, I could have done
-90*-40+2*40+1*90=3770
...
and so on.
i have to estimate each product or quotient are these right?
-72 x 57 i got:
-4104 est -4000
-92 x (-41) i got
3772 = est: 3800
-83 x 52 i got:
-4316 est: -4500
-803 x (-106) i got
85228 est: 85000
49 x 61
2989 est: 3000
-476 / 90
-5.288 est:
-500/ 90 ?
538 / (-63)
500 / 60 ?
479 / (-61)
500 / (-60)?
5 answers
i understand what you said and agree i just was not sure if i was doing rignt or not? i have to estimate each product or quotient are these right? i got stuck on division ones:
-72 x 57 i got:
-70 x 60 - -4200
-92 x (-41) i got
3600
-83 x 52 i got:
-80 x 50 = -40000
-803 x (-106) i got
-800 x (-100) = 80000
49 x 61 i got 50 x 60 = 3000
i don't know about these division ones
-476 / 90
-500/ 90 ?
538 / (-63)
500 / 60 ?
479 / (-61)
500 / (-60)?
-72 x 57 i got:
-70 x 60 - -4200
-92 x (-41) i got
3600
-83 x 52 i got:
-80 x 50 = -40000
-803 x (-106) i got
-800 x (-100) = 80000
49 x 61 i got 50 x 60 = 3000
i don't know about these division ones
-476 / 90
-500/ 90 ?
538 / (-63)
500 / 60 ?
479 / (-61)
500 / (-60)?
-476 / 90
-5.288 est:
-500/ 90
I would divide 476/100=4.76 and add 10%=5.24
538 / (-63)
500 / 60 ? Good
479 / (-61)
500 / (-60)? or try 480/60=8
-5.288 est:
-500/ 90
I would divide 476/100=4.76 and add 10%=5.24
538 / (-63)
500 / 60 ? Good
479 / (-61)
500 / (-60)? or try 480/60=8
so how about
-476 divide by 90
est:
-450 divide by 0 = -5
538 divide by (-63)
est: 540 divide by (-60) = -9
479 divide by (-61)
est: 480 divide (-60)
= -8
-476 divide by 90
est:
-450 divide by 0 = -5
538 divide by (-63)
est: 540 divide by (-60) = -9
479 divide by (-61)
est: 480 divide (-60)
= -8
so how about
-476 divide by 90
est:
-450 divide by 90 = -5 [an acceptable estimate]
If you want to be fancy, try
-476/90 ~ 480/90 ~ 48/9 ~ 16/3 ~ 5.3
538 divide by (-63)
est: 540 divide by (-60) = -9 [OK]
479 divide by (-61)
est: 480 divide (-60) [OK]
= -8
-476 divide by 90
est:
-450 divide by 90 = -5 [an acceptable estimate]
If you want to be fancy, try
-476/90 ~ 480/90 ~ 48/9 ~ 16/3 ~ 5.3
538 divide by (-63)
est: 540 divide by (-60) = -9 [OK]
479 divide by (-61)
est: 480 divide (-60) [OK]
= -8