Download presentation

Presentation is loading. Please wait.

Published byMichael Randall Modified over 2 years ago

1
MrV’s Shorthand Division (by Single Digits 2, 5, and 3) It Helps You Do Prime Factorization using Factor Trees: If you are SURE that a long number divides exactly by 2, 5, or 3, you can use Shorthand Division to quickly find the other factor. Easy Tests for Divisibility: 2: Only even numbers (ending with 0, 2, 4, 6, or 8) divide by 2 Examples: 34,138 will divide by 2, but 123,243 will not 5: Only numbers ending with 0 or 5 will divide by 5 Examples: 3,005 will divide by 5, but 3,002 will not 3: Only numbers with a digit sum that divides by 3 also divide by 3 Examples: 15,201 will divide by 3, but 15,202 will not 1+5+2+0+1=9 1+5+2+0+2=10 7: There’s no easy test - Divide by 7 (use either kind of division) to see if you get a 0 remainder 4, 6, 8, and 9: Why bother? Check for the primes first. If 2 and 3 will not divide, then these other digits will not

2
How to do Shorthand Division Let’s use 6408 divided by 2 as an example… Write the division with the division symbol upside down, and build the quotient underneath it --> 2 ) 6 4 0 8 Work left to right, one digit at a time 2 into 6 is 3 2 into 4 is 2 2 into 0 is 0 2 into 8 is 4 2 ) 6 4 0 8 2 ) 6 4 0 8 2 ) 6 4 0 8 2 ) 6 4 0 8 3 3 2 3 2 0 3 2 0 4 It’s easy if each little division goes evenly. But if not… ? Let’s call any remainders “carries.” (They get carried to the next digit) 2 into 7 is 3, r 1 2 into 12 is 6 2 into 1 is 0 r 1 2 into 18 is 9 2 ) 7 1 2 1 8 2 ) 7 1 2 1 8 2 ) 7 1 2 1 1 8 2 ) 7 1 2 1 1 8 3 3 6 3 6 0 3 6 0 9 Many students can do these little divisions in their heads, but some may find MrV’s Tables are useful when dividing by 3, 5 and 7 quotient

3
Dividing a number by 2: Either it goes exactly, or there is a remainder of 1 You can use MrV’s Times Table. You may find it easier if you do some computations in your head Long Division: Shorthand Division: (leave some space between the digits) Long Division compared to Shorthand Division 75 2 into 8 goes 4, exactly 2 into 7 goes 3, with 1 left over – making the next digit 1 2 2 into 12 goes 6, exactly 2 into 0 goes 0, exactly 2 into 5 goes 2, with 1 left over – making the next digit 18 2 into 18 goes 9, exactly

4
Dividing a number by 3: Either it goes exactly, or there is a remainder of 1 or 2 You can use MrV’s Times Table. You may find it easier if you do some computations in your head Long Division: Shorthand Division: (leave some space between the digits) Long Division compared to Shorthand Division 4 2 3 into 6 goes 2, exactly 3 into 4 goes 1, with 1 left over – making the next digit 1 2 3 into 12 goes 4, exactly 3 into 2 goes 0, with 2 left over – making the next digit 2 7 3 into 27 goes 9, exactly

Similar presentations

OK

© 2010 Pearson Prentice Hall. All rights reserved. CHAPTER 4 Number Representation and Calculation.

© 2010 Pearson Prentice Hall. All rights reserved. CHAPTER 4 Number Representation and Calculation.

© 2017 SlidePlayer.com Inc.

All rights reserved.

Ads by Google

Ppt on summary writing Ppt on various types of web browsers and their comparative features Ppt on work life and leisure in london Ppt on hydrogen fuel cell Flexible oled display ppt on tv Ppt on earth day 2013 Ppt on digital multimedia broadcasting Ppt on asymptotic notation of algorithms to solve Ppt on historical places in jaipur Ppt on mobile and wireless networks