Lesson 6 Another Addition Algorithm

Warm-up Notice and Wonder: Another Curious Table

What do you notice? What do you wonder?

$+$	$98$	$99$	$100$	$101$	$102$
$98$		$197$		$199$
$99$	$197$		$199$		$201$
$100$		$?$		$?$
$101$	$199$		$201$		$203$
$102$		$201$		$203$

Here are two algorithms for adding $367 + 231$ .

Han’s algorithm

Elena’s algorithm

Discuss with your partner:

Here are two algorithms for adding $365 + 182$ .

Han’s algorithm

Elena’s algorithm

How do the algorithms show the 14 tens differently?

Try Elena’s algorithm to find the value of each sum.

Here is Elena’s algorithm for finding $273 + 481$ .