Left to Right Subtraction

When subtracting two-digit numbers, your trying to simplify the problem so that you are subtracting a one-digit number For example:

$$\begin{array}{r} 47 \\ - 32\ (30+2) \\ \hline \end{array}$$

After each unit you subtract (tens, ones) the problems becomes a new subtraction however it is easier. First we subtract $30$ from $47-30 = 17$ then we subtract $2$ to reach the simpler subtraction problem $17-2$ for a final answer of $15$. The problem can be diagrammed this way

$$\underbrace{47-32}_{\text{(first subtract 30)}} \;=\; \underbrace{17-2}_{\text{(then subtract 2)}} \;=\; 15$$

These problems become more difficult when you add borrowing into the mix (occurs when a larger digit is being subtracted from a smaller one).

These problems can be hard but we