Numbers

Question 1

What is a prime number?

Answer 1

Can be divided by itself and 1

Question 2

Is 1 a prime number

Answer 2

No

Question 3

How many prime numbers between 1 and 100

Answer 3

20

Question 4

When 2 prime numbers are added the answer is 22, what are the PN?

Answer 4

19 and 3

Question 5

How to tell if a number is prime?

Answer 5

Eliminate not prime numbers

Divisible by 2 - not prime
Then check 3, 5, 7, 11, 13

If a number ends in 0, 2, 4, 5, 6 or 8 then it’s not prime (except for 2 and 5)

If the sum of the digits is a multiple of 3, then the number is not prime (except for 3)

Using these methods can eliminate about 75% of numbers

Question 6

What is a factor of another number?

Answer 6

Numbers that evenly divide the first number.

Question 7

What is a prime factor

Answer 7

A factor that is also a prime number

Question 8

What is least common multiple

Answer 8

The lowest number which is a multiple of both two numbers

Question 9

What is the highest common factor

Answer 9

Highest factor that is the same for both numbers

Question 10

How do you work out least common multiple in a Venn diagram?

Answer 10

1. Break each number down into a prime factor tree
2. Place common prime factors in middle of 2 circle Venn diagram
3. Place remaining prime factors in individual circles.
4. LCM is all numbers in the circles times each other

Question 11

How do you work out highest common factor in a Venn diagram?

Answer 11

1. Break each number down into a prime factor tree
2. Place common prime factors in middle of 2 circle Venn diagram
3. Place remaining prime factors in individual circles.
4. HCF is multiple numbers in the intersection of the Venn.

Question 12

What are powers?

Answer 12

The small number is how many times the base number is multiplied by itself

Question 13

What is BIDMAS

Answer 13

The order for operations:

1. Brackets
2. Index (powers)
3. Divide
4. Multiply
5. Add
6. Subtract

Question 14

What is a square number?

Answer 14

A number times itself

Question 15

What is a square root of a number?

Answer 15

What number times itself equals the first number

Question 16

What is a cube number?

Answer 16

A number times itself 3 times.

Question 17

What is the triangle number rule?

Answer 17

x(n)=n(n+1)/2

Question 18

What are sequence rules?

Answer 18

1. Check what happens between each term
2. This is the term-to-term rule
3. nth term is the formula for caluclating any value in a sequence (example nth term = 6n+1, value of 10th term in sequence is 6(10)+1=61.