HCF and LCM Worksheet-6

HCF and LCM Worksheet-6

1. Find the LCM of 26 and 34.

(a) 234               (b) 446               (c) 442               (d) 421

2. Jay has a pack of cards. If he makes group of 3 cards or group of 8 cards or group of 12 cards, no card is left over. How many cards does he have in the pack?

(a) 24                  (b) 12                  (c) 16                  (d) 21

3. Paul has two mystery numbers in his mind. Their least common multiple is 45 and greatest common factor is 3. Which two numbers does he have in his mind?

(a) 3 and 4         (b) 9 and 15       (c) 9 and 18       (d) 6 and 20.

4. Find the LCM of 36 and 100.

(a) 600               (b) 180               (c) 90                  (d) 900

5. Find the least common multiple of 14, 21 and 32.

(a) 124                (b) 1,120            (c) 210                (d) 672

6. Both Maria and Katrina are taking piano classes. Maria has piano class every 3rd day and Katrina has her class on every 5th day. Which is true about their classes?

(a) They will both have a class on the 12th day.

(b) They will both have a class on the 18th day.

(c) They will both have a class on the 15th day.

(d) They will never have a class on the same day.

7. Find the LCM of 16, 25 and 40.

(a) 150                (b) 400               (c) 80                 (d) 300

8. Which shows the prime factorization of 90?

(a) 2 × 2 × 3 × 5                           (b) 2 × 3 × 5 × 5

(c) 3 × 3 × 3 × 5                           (d) 2 × 3 × 3 × 5

9. The prime factorization of 125 is _______.

(a) 3 × 5 × 5 × 5                            (b) 5 × 5 × 5

(c) 3 × 2 × 5 × 5                            (d) 3 × 3 × 7 × 5

10. Which is a prime number?

(a) 91                  (b) 64                 (c) 50                  (d) 79

11. Which is NOT a prime number?

(a) 443               (b) 149                (c) 49                  (d) 19

12. Which is a composite number?

(a) 29                  (b) 121                (c) 53                  (d) 101

13. Which shows the prime factorization of 147?

(a) 3 × 7 × 7      (b) 3 × 3 × 7      (c) 3 × 5 × 6      (d) 3 × 5 × 7

14. Find the prime factorization of 420.

(a) 2 × 2 × 2 × 5 × 7                    (b) 2 × 2 × 5 × 5 × 7

(c) 2 × 2 × 3 × 3 × 7                    (d) 2 × 2 × 3 × 5 × 7

15. Find the prime factorization of 1029.

(a) 2 × 3 × 3 × 7                           (b) 3 × 7 × 7 × 7

(c) 2 × 2 × 5 × 7 × 13                   (d) 2 × 2 × 3 × 7 × 11

16. Which shows the prime factorization of 1,242?

(a) 2 × 3² × 23  (b) 2 × 3³ × 21  (c) 2 × 3³ × 23  (d) 2 × 5³ × 11

17. Which shows the prime factorization of 225?

(a) 3 × 3 × 3 × 5 × 5 × 5             (b) 2 × 3 × 5 × 6

(c) 3 × 3 × 5 × 5                           (d) 9 × 5 × 5

Answer Key:

(1)-(c); (2)-(a); (3)-(b); (4)-(d); (5)-(d); (6)-(c); (7)-(b); (8)-(d); (9)-(b); (10)-(d); (11)-(c); (12)-(b); (13)-(a); (14)-(d); (15)-(b); (16)-(c); (17)-(c)