Word Problems Involving Greatest Common Factor and Least Common Multiple

After learning about greatest common factor (gcf) and least common multiple (lcm), kids should know where these concepts apply in our daily life. Word problems are the links which relate mathematics to our daily life.

For example; there are two neon signs outside a store, one is red and the other is blue. Red sign flashes after every 6 seconds and the blue sign flashes after every 20 seconds. After how many seconds they both flash together?

To solve the above problem if kids know least common multiple (lcm) of 6 and 20 then they can come up with the answer; after 60 seconds both signs flash together.

The key word is together for lcm problems (some times smallest is used). In gcf problems the key word used is greatest (some times maximum), very easy to remember greatest in gcf and greatest in word problem! Isn't it?

Below is a page from an online resource and I have given the hints on the first page. There are 3 pages of the exercise which can be printed using the PDF link given below the image;

PDF Link to all 3 Pages of Worksheet

Below are the links to 2nd grade and 3rd grade math pages, where you can print all the content for 2nd and 3rd grade math students;

2ND GRADE MATH CORE CURRICULUM

3RD GRADE MATH CORE CURRICULUM