Show:
LCM
HCF
Divisibility Rules & Prime Factorization
HCF and LCM
Indices and More
100
Find the LCM of 12 and 18
36
100
Find the HCF of 30 and 72
6
100
Which of these numbers is a factor of 450? 2,3,4,5 or 6
2,3,5,6
100
Samantha has two pieces of cloth. One piece is 72 cm wide and the other piece is 90 cm wide. She wants to cut both pieces into strips of equal width that are as wide as possible. How wide should she cut the strips?
HCF question! Answer is 12 cm.
100
Which is bigger? 2^5 or 5^2?
2^5 = 2 x 2 x 2 x 2 x 2 = 32 5^2 = 5 x 5 = 25
200
FInd the LCM of 24 and 30
120
200
Find the HCF of 24 and 48
24
200
Which of these numbers is a factor of 424? 2,3,4,5, or 6
2 and 4
200
A radio station gave away a 100kr to every 50th caller. Every 30th caller received free concert tickets. How many callers must get through before one of them receives both a coupon and a concert ticket?
LCM question! The 150th caller will get both tickets and money.
200
Which is bigger? 1^100 or 100^1
100^1
300
Find the LCM of 16, 20 and 24
480
300
Find the HCF of 36 and 80
4
300
Give the prime factorization of 1602.
2 • 3^2 • 89
300
Mrs. Evans has 120 crayons and 30 pieces of paper to give to her students. What is the largest # of students she can have in her class so that each student gets equal # of crayons and equal # of paper.
HCF question! 30 students is the answer.
300
Between which two integers (whole numbers) does √29 lie?
4 x 4 = 16, 5 x 5 = 25, 6 x 6 = 36 29 is between 25 and 36, so √29 is between 5 and 6.
400
Find the LCM of 1 and 101
101
400
Find the HCF of 72, 36 and 60
12
400
Give the prime factorization of 144.
2^4 x 3^2 i
400
Ben exercises every 12 days and Isabel every 8 days. Ben and Isabel both exercised today. How many days will it be until they exercise together again?
This is an LCM question. The LCM of 8 and 12 is 24, so in 24 days, they will exercise together.
400
Put in order from smallest to biggest: 10^2, √101, 99
11
500
Find the LCM of 4, 15 and 20
1200
500
Find the HCF of 15, 45 and 75
15
500
Give the prime factorization of 726.
2 x 3 x 11^2
500
Six bells start ringing together and ring at intervals of 2, 4, 6, 8 10 and 12 seconds respectively. In 12 minutes, how many times do they ring at the same time?
This is a LCM question. The bell that rings every 12 seconds will ring 60 times in 12 minutes. Because the bells that rings every 2, 4, and 8 seconds are factors of 12, they will also ring at these times, so we don't have to count these. The LCM of 8, 10 and 12 is 120, so every 2 minutes, these bells will ring at the same time. So in 12 minutes, the bells will ring 6 times together.
500
Estimate the square root of 94 to one decimal place.
9 x 9 = 81 10 x 10 = 100 94 is closer to 100 than 81, so an estimate between 9.3 to 9.8 is good.