Lesson 18 Divide with Partial Quotients

Warm-up Number Talk: Divide by 3

Find the value of each expression mentally.

Find the value of $465 \div 5$ . Show your reasoning. You may use base-blocks if you find them helpful.

Here’s how Priya finds the value of $465 \div 5$ .

$\begin{aligned} 400 \div 5 & = 80 \\ 60 \div 5 & = 12 \\ 5 \div 5 & = 1 \\ \overset{―}{465 \div 5} & \overset{―}{= 93} \end{aligned}$

Tyler uses a different method to find the value of $465 \div 5$ . Let’s compare Priya’s and Tyler’s work.

Priya’s method

$\begin{aligned} 400 \div 5 & = 80 \\ 60 \div 5 & = 12 \\ 5 \div 5 & = 1 \\ \overset{―}{465 \div 5} & \overset{―}{= 93} \end{aligned}$

Tyler’s method

How are Priya and Tyler’s methods alike? How are they different? List as many similarities and differences as you can find.
Why do you think Tyler uses subtraction in his method?
Show how Tyler might record the process of finding the value of $428 \div 4$ .

Here are two incomplete calculations of $864 \div 4$ . Complete each calculation to find the value of the quotient.

$\begin{aligned} 800 \div 4 & = 200 \\ 40 \div 4 & = \\ 20 \div 4 & = \\ 4 \div 4 & = \\ \overset{―}{864 \div 4} & \overset{―}{=} \end{aligned}$