Multiplication
What is 324 × 3?
972
What is 1,440 ÷ 8?
180
Which pair of numbers has 5 as a common factor?
A. 12 and 25
B. 15 and 35
C. 18 and 28
D. 21 and 32
B. 15 and 35
Both numbers can be divided evenly by 5.
Question: There are 1,200 stickers. They are divided equally among 6 students.
How many stickers does each student receive?
Answer: 200 stickers
Question: A student says:
“If 6 × 8 = 48, then 48 ÷ 6 = 8.”
Is the student correct?
Answer: Yes!
Multiplication and division are related inverse operations.
6 × 8 = 48
So:
48 ÷ 6 = 8
What is 1,205 × 4?
4,820
2,856 ÷ 7?
408
Question: Which number is a multiple of both 4 and 6?
A. 18
B. 20
C. 24
D. 30
Answer: C. 24
24 = 4 × 6
Question: A farmer has 8 rows of plants. Each row has 135 plants.
How many plants are there altogether?
Answer: 1,080 plants
135 × 8 = 1,080
Question: A student says:
“The factors of 18 are 1, 2, 3, 6, 9, and 18.”
Is the student correct?
Answer: Yes!
These numbers all divide evenly into 18.
What is 2,736 × 5?
13,680
A number is divided by 6. The quotient is 245 and the remainder is 3.
What is the original number?
1,473
Question: List all the factors of 24.
Answer: 1, 2, 3, 4, 6, 8, 12, and 24
Question: A concert has 1,500 people attending.
There are 4 times as many children as adults.
How many adults are there?
Answer: 300 adults
Think of the group as 5 equal parts:
1 part = adults
4 parts = children
5 parts = 1,500
1,500 ÷ 5 = 300
So there are 300 adults.
Question: A student solves:
2,468 × 4 = 9,872
Is the answer correct?
Answer: Yes!
2,468 × 4 = 9,872
A school orders 246 notebooks for each of its 7 classrooms.
How many notebooks does the school order altogether?
Answer: 1,722 notebooks
246 × 7 = 1,722
Question: A school has 3,276 pencils and puts them equally into 9 boxes.
How many pencils go into each box?
364 pencils
3,276 ÷ 9 = 364
Find the least common multiple of 6 and 8.
24
Multiples of 6:
6, 12, 18, 24...
Multiples of 8:
8, 16, 24...
The first number they have in common is 24.
Question: A bakery makes 2,400 cookies.
It packs 8 cookies in each bag.
The bags are then placed equally into 6 large boxes.
How many bags are in each large box?
Answer: 50 bags
First:
2,400 ÷ 8 = 300 bags
Then:
300 ÷ 6 = 50 bags
Question: A student solves:
1,925 ÷ 5 = 385
Is the student correct?
Answer: Yes!
Check using multiplication:
385 × 5 = 1,925
So the division is correct.
Question: A theater has 328 seats in each section. There are 6 sections.
Before the show, 275 seats are reserved for staff and performers.
How many seats are available for the audience?
Answer: 1,693 seats
328 × 6 = 1,968
1,968 − 275 = 1,693
Question: A number is divided by 8.
The quotient is 317 and the remainder is 5.
What is the number?
Answer: 2,541
317 × 8 = 2,536
2,536 + 5 = 2,541
Question: A bell rings every 6 minutes. Another bell rings every 8 minutes.
They ring together at exactly 12:00.
After how many minutes will they next ring together?
Answer: 24 minutes
The least common multiple of 6 and 8 is 24.
So they will ring together again at 12:24.
Question: A school has 2,875 students attending a special event.
Each bus can carry 45 students.
What is the least number of buses the school needs?
Answer: 64 buses
2,875 ÷ 45 = 63 remainder 40
Since 63 buses would not be enough to carry everyone, the school needs one additional bus.
63 + 1 = 64 buses
Question: Two students are solving the same problem:
3,256 ÷ 7
Who is correct? Explain.
Answer: Maya is correct.
Check Sam's answer:
464 × 7 = 3,248
That is 8 less than 3,256, so 464 is not the complete answer.
Check Maya's answer:
465 × 7 = 3,255
There is 1 left over.
So:
3,256 ÷ 7 = 465 remainder 1