Divisibility Rules / LCM & GC
There are 15 chocolate muffins and 20 vanilla muffins.
The baker wants to pack them into boxes with the same number of each flavor and no muffins left over.
What is the greatest number of boxes she can make?
GCF of 15 and 20 = 5 boxes
5.68 - 4.23
1.45
8.2 x 6.5
53.3
A baker uses 9.6 kg of flour to make 8 cakes.
How much flour is used for each cake?
9.6 ÷ 8 = 1.2 kg per cake
For which 2 operations (addition, subtraction, multiplication, division) do you need to line up the decimal points?
Addition and Subtraction
How do you know that 999 is divisible by 3 and 9 but not by 6?
To be divisible by 6 the number must be divisible by 3 and 2. This number is not divisible by because the last digit is not even.
67.75 - 8.1
59.65
4.22 x 8.1
34.182
A gas bill for $87.12 is split evenly among 4 people.
How much does each person pay?
87.12 ÷ 4 = $21.78
For which operations (addition, subtraction, multiplication, division) do you need to count the number of digits after the decimal points?
Multiplication
The gym lights turn off automatically every 12 minutes, and the hallway lights every 18 minutes.
If both were turned off at 9:00 AM, when will they next turn off at the same time?
Find LCM of 12 and 18: 36 minutes
- Next at 9:36 AM
43.032 - ____ = 36.122
6.91
A car travels 6.8 km each minute. How far does it travel in 12.5 minutes?
6.8 × 12.5 = 85 km
55.08 / 9
6.12
What is the name for the answer to a multiplication problem?
Product
Mr. Baker, who is the principal of the school, needs to transport his entire school which consists of 324 students to a Spring Concert without the aid of large buses. Explain which of the following vehicles he can use without having any students left over?
Cross Over = no
Mini Van = Yes because 324 is divisible by 6
SUV = Yes because 324 is divisible by 4
A store had 245.78 kg of rice in stock. By the end of the week, 129.946 kg had been sold.
How much rice remains in stock?
245.78 − 129.946 = 115.834 kg
0.07 x 0.42
0.0294
28.77 / 0.7
41.1
A box of 12 hockey pucks has a mass of 1,876.84g. If the empty box has a mass of 64.6g, what is the mass of each hockey puck?
151.02g
Two runners start jogging around a circular track at the same time.
- Ali completes a lap in 8 minutes
- Hamza completes a lap in 10 minutes
How many minutes will it take before they are both at the starting point together again, and how many laps will each have run by then?
LCM of 8 and 10 = 40 minutes
- They’ll meet at the start again after 40 minutes
- Ali runs 5 laps, Hamza runs 4 laps
A runner jogged 12.875 km on Monday and 9.638 km on Tuesday.
How many more kilometers did the runner jog on Monday than on Tuesday
12.875 − 9.638 = 3.237 km
A small garden pond has .233 meters of water added every hour.
If water is added for 6.7 hours, how many meters of water are added in total?
0.233 × 6.7 = 1.5611 meters
A factory produces 1.299 tons of metal sheets. Each package contains 0.03 tons of sheets.
How many full packages can the factory make?
Full packages: 43
A gardener uses 3.75 kg of soil to fill one planter. He has 47.25 kg of soil in total.
a) How many full planters can he fill?
b) After filling those, he divides the remaining soil equally into 5 small pots. How much soil (to two decimals) goes into each small pot?
a) 47.25 ÷ 3.75 = 12 full planters
Total used = 12 × 3.75 = 45.00 kg
Remaining soil = 47.25 − 45.00 = 2.25 kg
b) 2.25 ÷ 5 = 0.45 kg in each small pot