We will be using these powerpoints in class to look at 'Multiplication' (11 Feb 2014):

Multiplication & Division

Practice test:

You should know your timestables up to 12's...

For this topic and our assessment you should also know:
BEDMAS
Multiples, Factors, Primes (including, HCF, LCM and Prime factors)
Powers and Roots
Doubling and Halving
Know multiplying by 10, 100, 1000 etc.
Dividing (including double/triple digit numbers divided by a single digit number)
Multiplying (up to triple digit number times a single digit; eg: 134 x 7)
Solving word problems for both times and divide.

Group Two need to know how to multiply using decimals (for Merit and Excellence grades)

Question to Solve


Write a word problem for the equation below and then solve it (put your name in brackets at the end of your problem).

12 x ___ = 204
12 t-shirts are packed in each box. How many boxes will be needed if there is an order of 204 t-shirts? ANS = 17 (Mrs Nathan)

If Rose sold fake flowers, in boxes, each box containing 12 fake flowers in each, what if someone order's enough for 204 flowers? How many boxes would Rose have sold? Answer 17 boxes. (Charlotte) :D Well done Charlotte!!!

Notes on multiples, factors and prime numbers:


Multiples: are like the timestables, so if you were asked to find the first five multiples of 3 you would use: (1x3), (2x3), (3x3), (4x3), (5x3) so your list of multiples would be: 3,6,9,12,15
Factors: are numbers that can multiply to make a larger number. Remember the term: factor x factor = product. So to find all the factors of 10 we look for 'pairs' of numbers that will multiply to make 10. Another 'tip' is to always start at the number 1, as 1 is a factor of all numbers.
Hence, factors of 10 would include (1x10), (2x5): factors of 10 (1,2,5,10). I will show you the 'Rainbow' method in class.
Prime numbers: are numbers that have only two factors; the number 1 and itself. For example 2 is the first prime number and also the only even number that is prime because it is only divisible by 1 and 2 (1x2=2). Here is the list of prime numbers up to 20, could you make a list up to 100? 2,3,5,7,11,13,17,19...
Square Numbers: are numbers to the power of 2.
Eg: 5² = 5 x 5
= 25
9² = 9 x 9
= 81
Any number can be an exponent (power)
Eg: 4³ = 4 x 4 x 4
= 64
Square roots
Eg: √16 = 4 (because 4 x 4 = 16)
√81 = 9 (because 9 x 9 = 81

Doubling & Halving

Eg: 74 x 5 = 37 x 10
= 370

84 x 50 = 42 x100
= 4200

Multiplying in parts

Eg: 74 x 6 = 70 x 6 + 4 x 6
= 420 + 24
= 444


Other notes we need are on: Highest Common Factors, Lowest Common Multiples and Prime Factors - can anyone write a definition for any of these?


Order of Operations (BEDMAS)

Watch this BEDMAS youtube clip to help you understand the order we do operations:


Multiplying by 10, 100, 1000


You simply place one zero after a whole number being multiplied by 10 Eg: 45 x 10 = 450

You simply place two zeros after a whole number being multiplied by 100 Eg: 34 x 100 = 3400

You simply place three zeros after a whole number being multiplied by 1000 Eg: 457 x 1000 = 457000

Multiplying numbers that are multiples of 10, 100 or 1000


First multiply the numbers that are not zero then count the zeros that are in the equation, these should be added on.
Eg: 20 x 30 = 600 - because 2 x 3 = 6; and two zeros because in 20 and 30 there are a total of two zeros.

Little bit more; Little bit less


Eg: 20 x 9 = 180 so 21 x 9 = 180 +9
= 189

Halving & Doubling


Eg: 74 x 5 = 37 x 10
= 370

84 x 50 = 42 x100
= 4200

Multiplying in parts


Eg: 74 x 6 = 70 x 6 + 4 x 6
= 420 + 24
= 444

Dividing by repeated adding


Eg: 24 divide by 6 is the same as counting up in 6's: 6, 12, 18, 24. So, 4 lots of 6 make 24.

Click Here to try this division game - you're the frog!!


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