Another way of looking at it is as if we are dealing with ratios
Given:
2 3/8
write this as
2
/1
+
3
/8
To be able to add the counts directly the number under 2 need to become 8. The numbers underneath (denominators) must be the same. The top number (numerator) is the actual count. The denominator is the size of what we are counting.
We can make the change by multiplying 2/1 by 1 but in the form of
