<< Chapter < Page Chapter >> Page >

Mathematics

Grade 5

Multiplication and division

Module 33

Division

Activity 1:

To be able to do mental arithmetic [lo 1.10]

  1. You already know how important it is to be able to do mental arithmetic. You also know how important it is to know your tables. Doing mental arithmetic and knowing your tables will help you do division correctly, too. Let us start right away! Do you also like dried sausage ("droëwors")? Work with a friend. Look closely at the two "sausage machines". The one who is first to give the answers is the fastest sausage maker!

Who won?

2. Work on your own and colour in according to the code: 4 = dark grey ; 5 = pink ; 6 = light grey ; 7 = black ; 9 = red.

3. Complete the tables:

34
3.1 Divided by 3 4 5 6 7 8 9
Remainders 1 ............ ............ ............ ............ ............ ............
61
3.2 Divided by 2 5 6 7 8 9 10
Remainders 1 ............ ............ ............ ............ ............ ............

4. Let us see how well you do in the following mental test. Complete it as quickly and accurately as you can:

4.1 35 – 5 – 5 – 5 = ............ 4.11 108 – 12 – 12 – 12 = ............
4.2 64 – 8 – 8 = ............ 4.12 72 – 9 – 9 = ............
4.3 42 ÷ 7 = ............ 4.13 Halve: 612: ............
4.4 54 ÷ 6 = ............ 4.14 Halve: 487: ............
4.5 ............ ÷ 7 = 8 4.15 Halve: 1 036: ............
4.6 ............ ÷ 12 = 6 4.16 ............ ÷ 9 = 4
4.7 28 ÷ 4 = ............ 4.17 ............ ÷ 8 = 6
4.8 280 ÷ 4 = ............ 4.18 60 ÷ ............ = 5
4.9 280 ÷ 40 = ............ 4.19 36 ÷ ............ = 4
4.10 2 800 ÷ 40 = ............ 4.20 3 600 ÷ 90 = ............

DID YOU KNOW?

Division is the inverse of multiplication.

Thus: 5 × 3 = 1515 ÷ 3 = 5 en15 ÷ 5 = 3

When I want to check a division sum, I multiply. When I check a multiplication sum, I divide

Activity 2:

To recognise, describe and use the reciprocal relation between multiplication and division

[lo 1.12.1]

1. Now use your knowledge of the "inverse" to complete the following:

1.1 If 26 × 17 = 442, then 442 ÷ 17 = ................ and 442 ÷ ................ = 17

  • If 24 × 30 = 720, then 720 ÷ ................ = 24 and 720 ÷ 24 = ................

DID YOU ALSO KNOW?

When we divide, we do the following:

REPEATED SUBTRACTION

12 ÷ 3 = 12 – 3 – 3 – 3 – 3 = 4

GROUPING

12 ÷ 3: We must divide 12 into 3 equal groups

DIVISION

12 ÷ 3: We must divide 12 equally between 3

123

Activity 3:

To recognise and represent numbers and to describe and compare them [lo 1.3]

1. Let us do revision. Do you remember what happens when we divide any number by 1? Work with a friend and find the answers to the following:

1.1 5 ÷ 1 = .................................. 1.2 86 ÷ 1 = ............................

1.3 359 ÷ 1 = .............................. 1.4 4 625 ÷ 1 = .......................

1.5 32 174 ÷ 1 = .........................

2. Write down a rule for dividing by 1.

BRAIN-TEASER!

If 5 ÷ 1 = 5 and 86 ÷ 1 = 86, then:

1 ÷ 5 = .........................

1 ÷ 86 = .........................

1 ÷ 359 = .........................

1 ÷ 4 625 = .........................

Thus, if 1 is the dividend, then the answer is always a...........................................

Questions & Answers

how did you get 1640
Noor Reply
If auger is pair are the roots of equation x2+5x-3=0
Peter Reply
Wayne and Dennis like to ride the bike path from Riverside Park to the beach. Dennis’s speed is seven miles per hour faster than Wayne’s speed, so it takes Wayne 2 hours to ride to the beach while it takes Dennis 1.5 hours for the ride. Find the speed of both bikers.
MATTHEW Reply
420
Sharon
from theory: distance [miles] = speed [mph] × time [hours] info #1 speed_Dennis × 1.5 = speed_Wayne × 2 => speed_Wayne = 0.75 × speed_Dennis (i) info #2 speed_Dennis = speed_Wayne + 7 [mph] (ii) use (i) in (ii) => [...] speed_Dennis = 28 mph speed_Wayne = 21 mph
George
Let W be Wayne's speed in miles per hour and D be Dennis's speed in miles per hour. We know that W + 7 = D and W * 2 = D * 1.5. Substituting the first equation into the second: W * 2 = (W + 7) * 1.5 W * 2 = W * 1.5 + 7 * 1.5 0.5 * W = 7 * 1.5 W = 7 * 3 or 21 W is 21 D = W + 7 D = 21 + 7 D = 28
Salma
Devon is 32 32​​ years older than his son, Milan. The sum of both their ages is 54 54​. Using the variables d d​ and m m​ to represent the ages of Devon and Milan, respectively, write a system of equations to describe this situation. Enter the equations below, separated by a comma.
Aaron Reply
find product (-6m+6) ( 3m²+4m-3)
SIMRAN Reply
-42m²+60m-18
Salma
what is the solution
bill
how did you arrive at this answer?
bill
-24m+3+3mÁ^2
Susan
i really want to learn
Amira
I only got 42 the rest i don't know how to solve it. Please i need help from anyone to help me improve my solving mathematics please
Amira
Hw did u arrive to this answer.
Aphelele
hi
Bajemah
-6m(3mA²+4m-3)+6(3mA²+4m-3) =-18m²A²-24m²+18m+18mA²+24m-18 Rearrange like items -18m²A²-24m²+42m+18A²-18
Salma
complete the table of valuesfor each given equatio then graph. 1.x+2y=3
Jovelyn Reply
x=3-2y
Salma
y=x+3/2
Salma
Hi
Enock
given that (7x-5):(2+4x)=8:7find the value of x
Nandala
3x-12y=18
Kelvin
please why isn't that the 0is in ten thousand place
Grace Reply
please why is it that the 0is in the place of ten thousand
Grace
Send the example to me here and let me see
Stephen
A meditation garden is in the shape of a right triangle, with one leg 7 feet. The length of the hypotenuse is one more than the length of one of the other legs. Find the lengths of the hypotenuse and the other leg
Marry Reply
how far
Abubakar
cool u
Enock
state in which quadrant or on which axis each of the following angles given measure. in standard position would lie 89°
Abegail Reply
hello
BenJay
hi
Method
I am eliacin, I need your help in maths
Rood
how can I help
Sir
hmm can we speak here?
Amoon
however, may I ask you some questions about Algarba?
Amoon
hi
Enock
what the last part of the problem mean?
Roger
The Jones family took a 15 mile canoe ride down the Indian River in three hours. After lunch, the return trip back up the river took five hours. Find the rate, in mph, of the canoe in still water and the rate of the current.
cameron Reply
Shakir works at a computer store. His weekly pay will be either a fixed amount, $925, or $500 plus 12% of his total sales. How much should his total sales be for his variable pay option to exceed the fixed amount of $925.
mahnoor Reply
I'm guessing, but it's somewhere around $4335.00 I think
Lewis
12% of sales will need to exceed 925 - 500, or 425 to exceed fixed amount option. What amount of sales does that equal? 425 ÷ (12÷100) = 3541.67. So the answer is sales greater than 3541.67. Check: Sales = 3542 Commission 12%=425.04 Pay = 500 + 425.04 = 925.04. 925.04 > 925.00
Munster
difference between rational and irrational numbers
Arundhati Reply
When traveling to Great Britain, Bethany exchanged $602 US dollars into £515 British pounds. How many pounds did she receive for each US dollar?
Jakoiya Reply
how to reduced echelon form
Solomon Reply
Jazmine trained for 3 hours on Saturday. She ran 8 miles and then biked 24 miles. Her biking speed is 4 mph faster than her running speed. What is her running speed?
Zack Reply
d=r×t the equation would be 8/r+24/r+4=3 worked out
Sheirtina
Got questions? Join the online conversation and get instant answers!
Jobilize.com Reply

Get Jobilize Job Search Mobile App in your pocket Now!

Get it on Google Play Download on the App Store Now




Source:  OpenStax, Mathematics grade 5. OpenStax CNX. Sep 23, 2009 Download for free at http://cnx.org/content/col10994/1.3
Google Play and the Google Play logo are trademarks of Google Inc.

Notification Switch

Would you like to follow the 'Mathematics grade 5' conversation and receive update notifications?

Ask