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Cogito

Grade 1 Math · Chapter 8 · Lesson 3

Practice Worksheet

Adding Tens to Any Number

Add whole tens and watch the ones stay put.

10 problems · about 11 minutes · 1.NBT.C.4

NameDate

Figure — use these to answer the problems

Change the second number by tens. Watch the cubes stay the same.
First number
and Add tens
Altogether

Tens

3

Ones

2

12 + 20 = 32

First number12
Add tens20
Figure 1

Warm-Up Review

From earlier lessons. Loosen up before the new work.

4 problems

  1. From “Subtracting Tens From Tens”

    30 − 20 = ?

    Answer

  2. From “Adding Tens to Tens”

    20 + 10 = ?

    Answer

  3. From “One More, One Less, Ten More, Ten Less”

    Ten less than 34 is?

    Answer

  4. From “Ten More, Ten Less”

    What is ten more than 21?

    Answer

Warm Up

Straightforward practice. Get the method working first.

3 problems

  1. 16 + 20 = ?

    Answer

  2. When you add 10, does the ones digit change?

    • No. It stays the same.
    • Yes. It goes up by one.

  3. 15 + 10 = ?

    Answer

Build It Up

The same ideas with more to keep track of.

1 problem

  1. 12 + 20 = ?

    Answer

Stretch Yourself

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

2 problems

  1. 17 + 20 = ?

    Answer

  2. Two Bags

    Leo has 13 marbles. He finds a bag of 20. How many?

    Answermarbles