One equation that you could make is 5+2-(-3)
Physics: each of two or more atomic nuclei that have the same atomic number and the same mass number but different energy states.
chemistry: each of two or more compounds with the same formula but a different arrangement of atoms in the molecule and different properties.
List the GCF of 18 and 28
18: 1, 2, 3, 6, 9, 18
28: 1, 2, 4, 7, 14, 28
So 2 is the GCF because it is the greatest number that can divide by both numbers
It's 6!
When you multiply both the numerator and denominator by the same number, you will have an equivalent to the fraction you started with because the new fraction can be reduced to the original fraction.
2/3 = 4/6 = 6/9 = 8/12 = 10/15 = 12/15 etc.