My Math Forum  

Go Back   My Math Forum > High School Math Forum > Elementary Math

Elementary Math Fractions, Percentages, Word Problems, Equations, Inequations, Factorization, Expansion


Thanks Tree4Thanks
  • 2 Post By Monox D. I-Fly
  • 2 Post By Benit13
Reply
 
LinkBack Thread Tools Display Modes
October 26th, 2014, 01:05 AM   #1
Newbie
 
Joined: Oct 2014
From: Washington

Posts: 2
Thanks: 0

Exclamation Division example in Pre-Algebra book seems confusing

Hello guys and girls.

I purchased a used copy of Pre-Algebra Demystified, 1st edition from the bookstore recently in an effort to build myself a solid foundation for math success. I have quite a lot of catching up to do, and to be honest I'm not having an easy time with division.

My book provides an example that left me confused:
Divide 543 by 37

I get to a point where the problem looks similar to the following:
Code:
     _1__
37|543
    -37_
     173
The next step says to divide 3 into 17. Well, if you multiply 3 by 5, you get the closest you can get to 17 without going over. I would think the next number in the quotient should be the number 5. The book says, "Note: The answer 5 is too large, so try 4."

How is that determined? I am mystified as to why the book's author would exclude the reasoning for the statement.
Equals is offline  
 
October 26th, 2014, 01:37 AM   #2
Senior Member
 
Monox D. I-Fly's Avatar
 
Joined: Nov 2010
From: Indonesia

Posts: 2,001
Thanks: 132

Math Focus: Trigonometry
$\displaystyle 37\times4=148$, which is less than 173.
$\displaystyle 37\times5=185$, which is more than 173, thus 5 is too large.
Thanks from topsquark and Equals
Monox D. I-Fly is offline  
October 27th, 2014, 02:12 AM   #3
Senior Member
 
Joined: Apr 2014
From: Glasgow

Posts: 2,155
Thanks: 731

Math Focus: Physics, mathematical modelling, numerical and computational solutions
I imagine many people don't know their 37 times table, so the book is suggesting a subtle trick where you try looking only at the tens digit first. Monox's result is the best one, but can be tricky to do in your head.
Thanks from topsquark and Equals
Benit13 is offline  
Reply

  My Math Forum > High School Math Forum > Elementary Math

Tags
book, confusing, division, prealgebra



Search tags for this page
Click on a term to search for related topics.
Thread Tools
Display Modes


Similar Threads
Thread Thread Starter Forum Replies Last Post
Book for Algebra 1 amit New Users 1 June 29th, 2014 12:30 AM
a very confusing problem in my math book dennisdixon Algebra 4 March 1st, 2013 09:00 PM
Confusing algebra word problem matt93 Algebra 3 November 3rd, 2011 08:53 AM
Algebra book available. MathloverKK Math Books 0 October 24th, 2011 03:17 PM
Order of operation (division) in algebra sharp Algebra 10 December 22nd, 2010 04:50 PM





Copyright © 2019 My Math Forum. All rights reserved.