Common factors, multiples, prime numbers
What are the first 2 common multiples of 8 and 4?
8 and 16
6 + 2 × 3 =
12
1. 12 × 8 = ?
2. 15 × 6 = ?
3. 23 × 7 = ?
1. 96
2. 90
3. 16
1. 15 + 26 =
2. 34 + 18 =
3. 47 + 22 =
1. 41
2. 52
3. 69
A factory produces 236 toys every day.
How many toys does the factory produce in 27 days?
6,372 toys in 27 days
Find 2 numbers that are not common multiples of 5 and 2
Multiples of 5: 5, 10, 15, 20, 25, …
Multiples of 2: 2, 4, 6, 8, 10, 12, …
Common multiples of 5 and 2: 10, 20, 30, 40, … (multiples of 10)
So any number not a multiple of 10 would work.
8 + 6 × 2 − 4 ÷ 2 =
18
127 × 36 = ?
4572
1. 45 − 23 =
2. 78 − 34 =
3. 60 − 17 =
1. 22
2. 44
3. 43
A baker made 48 cupcakes. He packed them into boxes as follows:
Each small box holds 4 cupcakes.
Each large box holds 6 cupcakes.
He packed 3 small boxes and 2 large boxes.
How many cupcakes does he have left?
Answer: The baker has 24 cupcakes left
Step 1: Calculate cupcakes in small boxes
3 × 4 = 12 cupcakes
Step 2: Calculate cupcakes in large boxes
2 × 6 = 12 cupcakes
Step 3: Total cupcakes packed
12 + 12 = 24 cupcakes
Step 4: Subtract from total cupcakes
48 − 24 = 24 cupcakes
Find three different pairs of prime numbers that add up to 30.
7 + 23 = 30
11 + 19 = 30
13 + 17 = 30
12 ÷ 3 + 5 × (2 + 3) − 4 = ?
25
245 × 68 = ?
16,660
982 + 634 − 421 = ?
982 + 634 = 1,616,
1,616 − 421 = 1,195
Miss Jackson asks her students to pick a number between 1 and 50.
The number must be a prime number.
It must also be a factor of 36.
Finally, the number must not be a multiple of 5.
What numbers can the students choose?
Answer: 2 or 3
Factors of 36: 1, 2, 3, 4, 6, 9, 12, 18, 36
Prime numbers = 2, 3
Neither 2 nor 3 is a multiple of 5
Find 2 multiples of 9 that are not multiples of 3
There are no numbers that are multiples of 9 but not multiples of 3. ALL multiples of 9 are also multiples of 3.
Multiples of 3:
3, 6, 9, 12, 15, 18, 21, 24, 27, 30, 33, 36, …
Multiples of 9:
9, 18, 27, 36, 45, 54, 63, 72, 81, …
Write the correct sign < = >
18 ÷ 3 + 2 × 4 ? 14 − 1
18 ÷ 3 + 2 × 4 > 14 − 1
1,234 × 567
699,678
4,785 + 2,639 + 1,478 = ?
10,902
Martina buys 350g of Cheddar and 400g of Brie for a party.
Cheddar costs £5.60 per kg
Brie costs 80p per 100g
Martina pays with a £20 note
How much change does she get?
£14.84
Bart is thinking of a number. His number is a factor of 36. His number is also a factor of 60. His number is greater than 3.
Write 3 numbers Bart could be thinking of.
Factors of 36: 1, 2, 3, 4, 6, 9, 12, 18, 36
Factors of 60: 1, 2, 3, 4, 5, 6, 10, 12, 15, 20, 30..
Common factors: 1, 2, 3, 4, 6, 12
We need the ones greater than 3:
4, 6, 12
Insert brakets to make these calculations correct.
1. 8 + 6 × 2 = 28
2. 12 − 4 × 2 + 6 = 16
3. 5 + 3 × 4 − 2 = 15
1. (8 + 6) × 2 = 28
2. 12 − (4 × 2) + 6 = 16
3. 5 + (3 × 4) − 2 = 15
A tablet costs £125.60. A store sells 18 tablets in a week.
Question: How much money does the store make in that week?
£2,260.80
Ella has £250 in her savings account. She receives £75 from her birthday and spends £48 on books. She then earns £120 from babysitting.
How much money does Ella have in her savings account now?
£397
Adrian, Renee, and Isla count the money they have in their pockets.
Adrian has 15p more than Renee.
Renee has 10p more than Isla.
Altogether, they have 95p.
How much money does Adrian have?
Adrian has 45p