Section A: Practice Problems Add Without Making a Ten

Section Summary

Details

We added numbers within 100. We learned different methods to add by thinking about tens and ones and record our thinking with equations.

$23 + 45$

Add on tens then ones:

Base ten diagram, 3 groups with numbers below. First group, 2 tens 3 ones, below 23. Second group, 4 tens, below 63. Third group, 5 ones, below 68.

$23 + 40 = 63$
$63 + 5 = 68$

Add tens and tens and ones and ones:

Base ten diagram. Group of tens, 2 tens, 4 tens, labeled 60. Group of ones, 3 ones, 5 ones, labeled 8.

$20 + 40 = 60$
$3 + 5 = 8$
$60 + 8 = 68$

Problem 1 (Pre-Unit)

How many do you see?

Problem 2 (Pre-Unit)

There are 9 ducks in the pond.
There are 7 ducks on the grass.
How many ducks are on the pond and in the grass?
Show your thinking using drawings, numbers, or words.

Problem 3 (Pre-Unit)

Find the number that makes each equation true.

$10 +$ $= 18$
$17 -$ $= 7$
$9 + 8 =$
$19 =$ $+ 14$

Problem 4 (Lesson 1)

Find the value of each sum.
Show your thinking using drawings, numbers, or words.

$65 + 3$
$65 + 30$

Problem 5 (Lesson 2)

Find the value of $31 + 24$ .
Show your thinking using drawings, numbers, or words.

Problem 6 (Lesson 3)

Find the value of $26 + 53$
Show your thinking using drawings, numbers, words, or equations.
Can you find the value in a different way?

Problem 7 (Exploration)

Find different ways you can use 2 two-digit numbers to make 86.
Use the drawing or connecting cubes, if they are helpful.
Can you make 86 by adding a two-digit number to itself?

Problem 8 (Exploration)

Together Mai and Han have 75 counters.
How many counters could Mai have?
Then how many counters would Han have?
Find at least 5 different solutions.