Name _________________________________________________
Practice
5-3
Least Common Multiples
List the first three common multiples of the given numbers.
1. 3, 2
2. 3, 4
12, 24, 36
_____________
6, 12, 18
_____________
5. 3, 5
6. 2, 7
15, 30, 45
_____________
14, 28, 42
_____________
3. 5, 4
4. 2, 8
20, 40, 60
_____________
7. 6, 5
8, 16, 24
_____________
8. 13, 2
30, 60, 90
_____________
26, 52, 78
_____________
Find the LCM of each pair.
138 10. 3, 21 ________
21 11. 9, 5 _________
45
51
9. 6, 23 ________
12. 17, 3 ________
21 15. 2, 12 ________
35
165
12 16. 15, 11 _______
13. 7, 5 _________
14. 21, 7 ________
76 18. 6, 28 ________
46
84 19. 14, 18 _______
126 20. 23, 2 ________
17. 4, 19 ________
210 22. 11, 33 _______
33 23. 5, 15 ________
40
15 24. 8, 5 _________
21. 15, 14 _______
286 26. 3, 22 ________
66 27. 2, 34 ________
34 28. 15, 8 ________
120
25. 26, 22 _______
30 30. 12, 4 ________
12 31. 6, 10 ________
559
30 32. 43, 13 _______
29. 10, 15 _______
168
34 36. 24, 7 ________
24 34. 36, 45 _______
180 35. 17, 2 ________
33. 24, 3 ________
155
145 38. 27, 2 ________
54 39. 9, 10 ________
90 40. 31, 5 ________
37. 29, 5 ________
12
10
558 42. 2, 7 _________
14
41. 62, 9 ________
43. 6, 4 _________
44. 10, 2 ________
48 51. 10, 14 _______
70 52. 22, 4 ________
44
112 50. 16, 6 ________
49. 7, 16 ________
53. Marti works Monday through Saturday, so she has a day
off once every 7 days. She needs to give her dog some
medicine every 5 days. How often does she give her dog
medicine on her day off?
Every 35 days
__________________
54. The traffic signal at 4th and Main turns green every 6 minutes.
The signal at 5th and Broadway turns green every 4 minutes.
If both turned green at 12:15 P.M., when are the next three
times that both will turn green at the same time?
12:27 P.M., 12:39 P.M., 12:51 P.M.
__________________________________________________________________________
62
Use with pages 280–284.
© Scott Foresman • Addison Wesley 6
22 48. 7, 12 ________
84
20 46. 6, 11 ________
66 47. 11, 2 ________
45. 4, 10 ________