MATHS GCSE COMPLETE REVISION

Question 1

When estimating, what do you round to?

Answer 1

1sf

Question 2

Which part of the venn diagram is the HCF?

Answer 2

the intersection

Question 3

Which part of the venn diagram is the LCM?

Answer 3

All of it times together

Question 4

What are the 4 indice rules?

Answer 4

ya x yb = y*a+b

ya divided by yb = y*a-b

y*0 = 1

(y*a) b = yab

Question 5

What is the negative indice rule?

Answer 5

a-b = 1/ab

Question 6

What are the rules for standard form?

Answer 6

a x 10*n

a = any number between 1 and 10

n = any positive or negative interger

Question 7

What are the rules of standard form multiplication(shown through example)?

Answer 7

EX: (2x105) x (3x104)

2x3 = 6

104 x 105 = 10*9

Ans: 6 x 10*9

Question 8

Write 156 x 10*-7 in standard form.

Answer 8

Ans: 1.56 x 10*-5
however much you need to divide the first number by, you need to times the second one by.

Question 9

What is the equation for percentage change?

Answer 9

change/original x 100

Question 10

What is the equation for compound interest?

Answer 10

Initial x multiplier*time

Question 11

How can you turn recurring decimals to fractions(using an example of 0.444)

Answer 11

Ex: 0.444 = 0.4 (with dot on top for recurring)

10x = 4.4(with dot on top)

9x = 4
divided by 9

4/9 = x

Question 12

What is direct proportion?(using an example of a and b)

Answer 12

a ∝ b = a = kb

Question 13

What is inverse proportion?(using an example of a and b)

Answer 13

a ∝ 1/b = a = k/b

Question 14

Surds are irrational numbers. What does that mean?

Answer 14

They can’t be square rooted

Question 15

How do you simplify surds(using an example)?

Answer 15

EX: √28 > find the largest square number that is a factor of it > square numbers: 1,4,9 > √4 x √7 > 2√7

Question 16

How do you multiply surds(using an example)?

Answer 16

3√5 x 2√3 = 6√15

3 x 2 = 6

√5 x √3 = √15

Question 17

How do you multiply and simplify surds(using an example)?

Answer 17

Ex: 2√15 x 3√5 > 6√75 > Find the largest square > 1,4,9,25 > √25 x √3 > 5√3 > 6x(5√3) > 30√3

Question 18

How do you do surds addition(using examples)?

Answer 18

Ex:
√2 + √2 = 2√2

√3 + √7 = can’t be done

For questions like √20 + √80, find the largest square

Question 19

How do you rationalise surds denominators?(2 different examples)

Answer 19

Rationalise denominators = move square foot from bottom to top

Ex: 1/ √2 x √2/√2 = √2/2

Ex 2: 4 / 3 - √5
you have to times it by the conjugate

4 / 3 - √5 x 3 + √5/ 3 + √5
= (bottom half) (3-√5) (3+ √5) = 9 + 3 √5 - 3 √5 - 5 = 4
= (top half) 4 x (3+ √5)

Question 20

What is direct proportion?

Answer 20

y = kx

Question 21

What is inverse proportion?

Answer 21

a = k/b