James, caleb and abigail bought a pizza. james ate 1/6 of the pizza, caleb ate 1/4 of the pizza what fracion did james and caleb eat together

You have to add 1/6 and 1/4. The only way to do that is to find a common denominator.  The lowest number that both 6 and 4 go into is 12:

You have to multiply the 6 by 2 to get to 12, so you have to multiply the 1 by 2 to get the equivalent fraction of 2/12. Do the same with the 1/4: you have to multiply 4 by 3 to get to 12, so you have to multiply the 1 by 3 to get to the equivalent fraction of 3/12.