Chapter 6.3, Problem 7P

Rodrigo calculates $650÷15$ in the following way:

$150$	$\leftarrow 10$	$300$	$\leftarrow 20$
$\frac{+150}{\begin{array}{l}300\\ 600\end{array}}$	$\leftarrow 10$    $\leftarrow 20$    $\leftarrow 40$	$\frac{+300}{600}$	$\leftarrow 20$    $\leftarrow 40$    $43R5$
$\frac{+30}{630}$	$\leftarrow 2$    $\leftarrow 42$
$\frac{+15}{645}$	$\leftarrow 43$
$\frac{-5}{650}$	$\leftarrow \text{left}$

1. Explain why Rodrigo's method makes sense.

Write equations that correspond to Rodrigo's work and that demonstrate that $650÷15$ has whole number quotient 43, remainder 5.