Problem of the Month: June 2021

Practice your math skills with ACES Problem of the Month! Every ACES Playbook newsletter includes a fun brain teaser to get your wheels turning and give you a peek at what our students are learning. The June Problem of the Month comes directly from our summer program curriculum for 6th graders!

June 2021 Problem of the Month
Alex is excited to choose the number for her new basketball jersey! Her favorite Minnesota Lynx play is Layshia Clarendon, #7, and her favorite Minnesota Timberwolves player is Ricky Rubio, #9. Alex decides to select a jersey number that is the least common multiple (LCM) of her favorite players’ jersey numbers. What number will Alex wear when she hits the court?

Scroll down to see the solution!

Solution
The least common multiple (LCM) of two or more positive numbers is the smallest number which is a multiple of all of them. One way to find the LCM of two numbers is to list their multiples until you find the first one in common.

The multiples of 7 are: 7, 14, 21, 28, 35, 42, 49, 56, 63, 70, 77, 84,…

The multiples of 9 are: 9. 18. 27. 36. 45. 54. 63. 72. 81. 90, 99,…

The smallest number that is a multiple of both 7 and 9 is 63. Thus, the LCM of 7 and 9 is 63. Alex will take to the court wearing a jersey #63!

Another method: The LCM of two numbers, a and b, can also be found using the following formula: LCM(a,b) = (a × b)/GCD (a,b)

GCD(a,b) is the greatest common divisor, the largest number that evenly divides both a and b.

The greatest common divisor of (7,9) = 1

Therefore, using the formula above, LCM of 7 and 9 = (7 × 9)/1

= 63/1 = 63

LCM of 7 and 9 = 63