To find the GCF, first you must factor the 2 or more numbers. The GCF is the highest factor the numbers have in common. for example: you have 12 and 8. If you factor out the numbers for 12, you get 1,2,3,4,6,12 For 8, you get: 1,2,4,8 the GCF of this pair is 4 because it is the highest number that goes into both 8 and 12. To find the LCM, you must find the first number that was multiplied and it must be the same. lets take 3 and 5. Multiply 3 by as many numbers you can think of. For now, lets just go up to 10. 3, 6, 9, 12 15, 18, 21, 24, 27, 30 now to the same for 5: 5, 10, 15, 20, 25, 30, 35, 40, 45, 50 in both 3 and 5, the first set of numbers that match in 30- therefore the LCM of 3 and 5 in 30. I hope this helps!
If she plans to use 10 intervals and the highest number in the data set is just under 100, then it makes sense to split the histogram into ten intervals of 10.
