Numbers Flashcards
Natural Numbers (N)
Positive whole numbers
Eg. 1,2,3,4,5,6
Factor
a number that divides evenly into another number
pairs of factors
a pair of numbers that multiply together to give said number.
Eg. Pairs of factor of 12 = 1,12 2,6 3,4
Prime Numbers (P)
numbers that only have 1 pair of factors. They are 1 and the selected number.
Highest Common Factor (HCF)
The largest number that divides into both numbers.
Eg. 36: 1,2,3,4,6,9,12,18,36
54: 1,2,3,6,9,18,27,54
HCF: 18
Indices (How to put together)
Eg. 4².
Base: 4
Index: ²
Say: 4 squared
Expand: 4×4
Answer: 16
Associative & Commutative
Same answer even when switched around
Eg. Commutative: 4 + 6 = 6 + 4
Associative: (6x4) x 8 = 6 x (4x8)
Integers (Z)
Whole positive and negative numbers including 0.
Rounding
If number <5 round down. If it is 5 or > round up
Eg. Round to 2 significant numbers
482 -> down = 480
Eg. Round to 3 significant numbers
782,946 -> up = 783,000
Comparing numbers
< less than
> greater than
Eg. 4 < 6
-4 > -6
Reciprocal
Flip it upside down
Eg. 1/8 = 8/1 = 1
2/3 = 3/2 = 1 1/2
Numerator (fraction)
top half of a fraction
Denominator
Bottom half of a fraction
Adding Fractions(and subtracting)
- Make sure all fractions denominators are the same (if not find the LCM).
- add numerators
- the denominator stays the same for the answer (the one you changed if you changed it)
- Simplify if needed.
eg. 3/4 = 1/3 = 3(3)/4(3) = 1(4)/3(4) = 9/12 + 4/12 = 13/12 = 1 1/12 LCM: 12
Multiplying Fractions
- Multiply all numerators
- Multiply all denominators
- Simplify if needed
Eg. 2/5 x 3/7 = 2(3)/5(7) = 6/35
Dividing Fractions
Multiply by the reciprocal of the 2nd number.
Eg. 2/3 ÷ 1/4 = 2/3 x 4/1 = 2(4)/3(1) = 8/3
Possible Outcomes
Number of outcomes x number of outcomes.
Eg. Coin: 2
Dice: 6
6x2=12 outcomes
Changing a fraction to a decimal
divide numerator by denominator
changing a fraction/decimal to percentage
x100
to change a percentage to a fraction/decimal
divide by 100
finding a percentage
30 x 12/100 or 30 x 0.12
finding 100%
divide number and percentage by percentage and multiply by 100.
eg. 63%/63% = $7.25/63
1% = $0.115
x100
100% = $11.50
Discount and VAT
divide percentage by total percentage, same with total number.
multiply by 100
eg.
123%/123 = $2.50/123
1% = $0.020
x100
$2
x23
$0.46
Percentage Profit/loss
profit (or loss)/cost price x 100
Eg. I bought a mirror for $20 and sold it for $25
Profit=$25-20=$5
5/20 x 100 = 25%
