Number

Question 1

How do you estimate?

Answer 1

Round numbers to one significant figure.

Question 2

How do you write a number as a product of prime numbers in index form?

Answer 2

Use prime factor tree. Layout prime numbers smallest to largest.
Simplify matching numbers.

E.g.
180=
2x2x3x3x5

2²x3²x5

Question 3

How do work out a lowest common multiple?

Answer 3

Write out multiples the multiples till you find the ones that match.

E.g

There 15 pencils in a pack and 40 pens in a box.

15 30 45 60 75 90 105 120
40 80 120

Question 4

How do you work out the highest common factor?

Answer 4

Eirher

Write out the numbers and all their factors. Find the highest that matches.

Use the prime factor tree on both numbers.
Pair off matching numbers
Write the paired numbers in accending order and multiply

Question 5

How to you show inequalities on a number line.

Answer 5

Draw circles above numbers given.
Connect circles if between.
If if equal to number make circles solid
If less than leave circle hollow.
If greater than draw an arrow in that direction.

Question 6

How do you work out a percentage?

Answer 6

Find 10% or 1% and mutlipy.

Question 7

How do you work out a reverse percentage on a deduction.

Answer 7

Work out what percentage you have left.

And either
Devide number by left over percentage to get 1% and x by 100

Or divide left over percentage by what ever number gives you it’s 10% and devide the number you are working with with this number.

E.g
A mobile phone is reduced by 20% in a sale. The sale price is £500. What is the original.

20%:80%
500÷80=6.25x100=625

Or

80÷8=8 (10%)
500÷8

8 into 50=6 remainder 2
8 into 20= 2 remainder 4
8 into 40= 5
10% =62.5x10=625

Question 8

How do you work out a reverse percentage on an increase?

Answer 8

Divide increase by %in reased to find 1%
x100

Question 9

What is simple interest?

Answer 9

Interest that does not acumulate.

Question 10

When using a calculator how would you workout simple interest?

Use example £500 with 1.5% interest.

Answer 10

500×1.015=512

Question 11

What is compound interest?

Answer 11

Interest that acumulates.

Question 12

How would you work out compound interest.

Answer 12

Use calculator method multiplied to the power of the interval

e.g 150,000 at a rate of 2.4 for 4 years

150,000 x 1.024⁴

Question 13

How do you workout a deprication?

Answer 13

With a calculator.

Work out the remaining percentage after the deprecation and multiply as a decimal to the power of the interval.

E.g 4000 depricates by 20% over 3 years.

20% 80%
80%=0.8
4000x0.8³

Without

Find out percentage of the amount left each interval and takeaway

Question 14

How do you multply fractions?

Answer 14

Times the top numbers

Times the bottom numbers

Simplfy by dividing both numbers in the fraction by the top number.
E.g 6/12= 1/2

Question 15

How do you devide fractions?

Answer 15

Flip one of the fractions

Times the answers

Simplfy by dividing by the top number.

Makesure improper fractions are written as example 1 1/2

Question 16

What should you do with mixed fractions before performing adding or subtracting

Answer 16

Convert to improper fractions by timesing full number by bottom number and adding result to top number.

E.g 1 3/4

1×4= 4+3=7

7/4

Question 17

How do you add or subtract fractions?

Answer 17

Convert fractions to make common denominator.

To do this times the top and the bottom of one fraction by the bottom of the other and vise versa.

Eg 7/4 2/3

4x3=12 7x3=21 3x4=12 3x2=6

Then add or subtract the numerator only

Convert to mixed number by dividing numerator by donminator

Simplfy the answer further if able.

Question 18

How do you reverse a fraction to work out a total amount from a partial amount.

Answer 18

Devide the total amount by numerator and x by the denominator

E.g 2/5 is 18

2÷8=9
5x9=45

Question 19

How do you write large numbers in standard form?

Answer 19

Hop decimal point to the left to make the number between 1 and 10.

X by 10 to the power of how many jumps you make.

E.g 5600 = 5.6x10³

Question 20

How do you write a small number in standard form?

Answer 20

Hop the decimal to the right to make a number between 1 and 10.

X by 10 to the negative power of the amount of hops you made.

0.0034= 3.4x10 -³

Question 21

How do you work out how many combinations you have with a number of items and a number of choices.

Answer 21

Times the amount by the amount of choices.

Question 22

What happens when you devide by 0.5?

Answer 22

The answer doubles.