Matt CarrinoMatt CarrinoLong Division for Fourth-Grade MathLong Division for Fourth-Grade Math

What is long division?What is long division?

►Process of divisionProcess of division

►Divisor is usually a large numberDivisor is usually a large number

►Each step of the division is written outEach step of the division is written out

When is long division needed?When is long division needed?

►Either the divisor or the dividend contain 2 Either the divisor or the dividend contain 2 digits or moredigits or more

►You cannot figure out the problem in your headYou cannot figure out the problem in your head

►Answers cannot be found in your times tablesAnswers cannot be found in your times tables

Problems that do not need long divisionProblems that do not need long division

►Problems that can be found in your times tablesProblems that can be found in your times tables

►Easy enough to figure out in your headEasy enough to figure out in your head

►Problems we either learned or similar ones to Problems we either learned or similar ones to thosethose

For example…For example…

► 10 / 5 = ?10 / 5 = ?

► 81 / 9 = ?81 / 9 = ?

► 4 / 2 = ?4 / 2 = ?

► 22

► 99

► 22

Problems that need long division…Problems that need long division…

►Are more complicated than those problemsAre more complicated than those problems

►Usually have divisors and dividends of 2 digits Usually have divisors and dividends of 2 digits or moreor more

► Require you to learn from this presentation!Require you to learn from this presentation!

For example…For example…

►2222 / 112222 / 11

►240 / 4240 / 4

►999 / 3999 / 3

► Can you figure out those problems in Can you figure out those problems in your head?your head?

► You would need a calculator …You would need a calculator …

► unless, you took the steps in the unless, you took the steps in the following slides in order to solve the following slides in order to solve the problemsproblems

To Begin Long DivisionTo Begin Long Division

► Take the first digit of the Take the first digit of the dividend, and see if it is dividend, and see if it is divisible by 25.divisible by 25.

► 4 / 254 / 25► 4 is not divisible by 254 is not divisible by 25► So, place a 0 above the 4So, place a 0 above the 4

To Begin Long DivisionTo Begin Long Division

►Multiply the answer by the divisor.. Put result Multiply the answer by the divisor.. Put result under number divided intounder number divided into

►Subtract the bottom number from the top Subtract the bottom number from the top numbernumber

To Begin Long DivisionTo Begin Long Division

►Bring down the next number of the dividend.Bring down the next number of the dividend.

►Divide this number by the divisor. Divide this number by the divisor.

The Process of Long DivisionThe Process of Long Division

►25 goes into 42 one time. Put that number at the 25 goes into 42 one time. Put that number at the top. top.

►Now, multiply that 1 by 25 and put it under 42.Now, multiply that 1 by 25 and put it under 42.

The Process of Long DivisionThe Process of Long Division

►To get remainder, subtract bottom from topTo get remainder, subtract bottom from top

►Bring down the next number of the dividend.Bring down the next number of the dividend.

The Process of Long DivisionThe Process of Long Division

► Now, divide 175 by 25, Now, divide 175 by 25, the same way we have the same way we have been doingbeen doing

► ________ 25) 17525) 175► 25 / 1 = 0, so25 / 1 = 0, so► 00 ___ ___ 25)175 25)175

► 25 / 7 =0, so25 / 7 =0, so► 0000 ___ ___ 25)17525)175

We are left with We are left with 175 /25175 /25

The Process of Long DivisionThe Process of Long Division

►175 /25. How many times does 25 go into 175?175 /25. How many times does 25 go into 175?►25 * 7 = 175, so25 * 7 = 175, so► 7 7 ___ ___ 25)175 25)175 175 175 --- --- 0 0

The Process of Long DivisionThe Process of Long Division

►7 is our answer to this part of the process:7 is our answer to this part of the process:

►So,So,

The Process of Long DivisionThe Process of Long Division

►Now, take your answer and multiply by the Now, take your answer and multiply by the divisor. Put the result under the number divided divisor. Put the result under the number divided into.into.

The Process of Long DivisionThe Process of Long Division

►Subtract the bottom number from the top Subtract the bottom number from the top numbernumber

The Process of Long DivisionThe Process of Long Division

►There are no more answers to bring down, so There are no more answers to bring down, so our answer is……our answer is……

17!!!!!!!!17!!!!!!!!

BibliographyBibliography

►Long Division. (2004). Math is Fun. Retrieved Long Division. (2004). Math is Fun. Retrieved December 4, 2004, from December 4, 2004, from http://www.mathsisfun.com/long_division.htmlhttp://www.mathsisfun.com/long_division.html

►Long Division. (2001). Homo Excelsior. Retrieved Long Division. (2001). Homo Excelsior. Retrieved December 4, 2004, from December 4, 2004, from

http://www.homoexcelsior.com/omega.db/datumhttp://www.homoexcelsior.com/omega.db/datum/mathematics/long_division/6729/mathematics/long_division/6729