We know that $14-13=1$14−13=1.
Use this to find:
Use what you know about subtracting to find:
We know that $29-14=15$29−14=15.
We know that $38-25=13$38−25=13.
Know how many ones, tens, and hundreds are in whole numbers to at least 1000.
Generalise that whole numbers can be partitioned in many ways