Lesson 2 Relate Counting to Addition

- Let’s add within 10.

Warm-up Number Talk: 2 or 3 More

Find the value of each expression mentally.

$4 + 2$
$5 + 2$
$5 + 3$
$6 + 4$

Activity 1 More Shake and Spill

cup turned so two-color counters are spilling out

Priya is playing Shake and Spill.
She spills 7 red counters and 2 yellow counters.
How many counters did she spill in all?
Show your thinking using drawings, numbers, or words.
Equation:
Tyler spills 5 red counters and 3 yellow counters.
How many counters did he spill in all?
Show your thinking using drawings, numbers, or words.
Equation:
Clare spills 2 red counters and 8 yellow counters.
How many counters did she spill in all?
Show your thinking using drawings, numbers, or words.
Equation:
Han spills 3 red counters and 6 yellow counters.
How many counters did he spill in all?
Show your thinking using drawings, numbers, or words.
Equation:

Activity 2 Are They Both Right?

Kiran and Clare are finding the value of $2 + 7$ .

Kiran counted on from 2.

Two-color counters. Red, 2. Yellow counters, 7, with labels 3, 4, 5, 6, 7, 8, 9.

2 + 7 = \boxed{9}

Clare counted on from 7.

Two-color counters, 2 groups. Yellow, 7 counters. Red counters, 2, with labels 8, 9.

7 + 2 = \boxed{9}

How can both methods be correct?
Show your thinking using drawings, numbers, or words.

Activity 3 Practice Addition Within 10

Find the value of each sum.

$7 + 2 =$
$3 + 5 =$
$= 8 + 2$
$3 + 6 =$
$5 + 2 =$
$= 4 + 4$
$2 + 6 =$
$= 1 + 9$

Practice Problem

Problem 1

Find the value of each sum.

$6 + 2$
$1 + 8$
$2 + 7$
$9 + 1$