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Cogito

Grade 1 Math · Chapter 8 · Lesson 9

Practice Worksheet

When the Ones Make a Ten

Sometimes the ones fill up and you need a new ten.

10 problems · about 14 minutes · 1.NBT.C.4

NameDate

Figure — use these to answer the problems

Count the loose ones first. Then bundle ten of them.
First number
and Second number
Altogether

Tens

2

Ones

14

18 + 16 = 34

First number18
Second number16
Figure 1

Warm-Up Review

From earlier lessons. Loosen up before the new work.

4 problems

  1. From “Adding Two-Digit Numbers”

    21 + 14 = ?

    Answer

  2. From “Word Problems Within 40”

    Whole 35, one part 15. Other part?

    Answer

  3. From “Tape Diagrams for Stories”

    Parts of 13 and 12. What is the whole?

    Answer

  4. From “Making the Next Ten”

    29 + 5 = ?

    Answer

Warm Up

Straightforward practice. Get the method working first.

3 problems

  1. 16 + 17 = ?

    Answer

  2. When do you need a new ten?

    • When the ones reach ten.
    • Every single time.

  3. 15 + 17 = ?

    Answer

Build It Up

The same ideas with more to keep track of.

1 problem

  1. 19 + 13 = ?

    Answer

Stretch Yourself

Mixed problems. Work out what kind of question it is before you start.

2 problems

  1. 14 + 12 = ?

    Answer

  2. Two Jars

    17 buttons in one jar and 15 in another. How many?

    Answerbuttons