Compatible Number Estimating
Date: 01/31/2002 at 20:23:16 From: Matt Ward Subject: Compatible numbers to estimate quotient My homework is on compatible numbers to estimate quotients - for example, 1,625 divided by 38. My Mom and Dad don't understand it either. Please help me to understand it. Thanks, Matt
Date: 01/31/2002 at 23:30:36 From: Doctor Peterson Subject: Re: Compatible numbers to estimate quotient Hi, Matt. _______ 38 ) 1625 You want to replace 38 with a nearby number that divides easily into something near 1625. (That's what "compatible" means: they play well together.) Try just rounding it up to the nearest 10: _______ 40 ) 1625 Is there a simple multiple of 40 near 1625? Yes, since 4 times 4 is 16, 40 times 40 is 1600. So our compatible numbers are ____40_ 40 ) 1600 Our estimate is 40. The actual quotient is 42.76, so we're not too far off. Here is a brief discussion in our archives: Compatible Number Method for Estimating http://mathforum.org/dr.math/problems/salman.09.10.01.html - Doctor Peterson, The Math Forum http://mathforum.org/dr.math/
Search the Dr. Math Library:
Ask Dr. MathTM
© 1994- The Math Forum at NCTM. All rights reserved.