Math Worksheet for 20-Year-Old Students

Instructions

1. Complete each mission in order. The questions begin with counting and build toward solving real-world problems.
2. Write neatly in the spaces provided.
3. You may use counters, coins, drawings, or a number line to help you.
4. Check your answers in the Answer Key when you finish.

Mission 1: Meet the Number 20

1. Trace or write the number five times.

   20 20 20 20 20

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2. Write the number that comes before 20: __

3. Write the number that comes after 20: __

4. Circle every number that is equal to 20.

   12 20 18 20 2 10 + 10 19

5. Complete the number sequence.

   16, 17, 18, __, __, __

6. Count backward from 20.

   20, 19, __, __, __, __, __

Mission 2: Show 20 in Different Ways

1. Draw 20 dots in the box below. Try arranging them in rows.

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2. Complete each number bond to make 20.

   a. 10 + __ = 20

   b. 15 + __ = 20

   c. 7 + __ = 20

   d. __ + 4 = 20

3. Write another addition sentence that equals 20.

   __ + __ = 20

4. Write a subtraction sentence that equals 20.

   __ - __ = 20

5. Use the words greater than, less than, or equal to.

   a. 20 is __ 18.

   b. 20 is __ 25.

   c. 20 is __ 20.

Mission 3: Solve and Sort

1. Solve each problem.

   a. 8 + 12 = __

   b. 14 + 6 = __

   c. 20 - 5 = __

   d. 20 - 9 = __

   e. 11 + 9 = __

   f. 20 - 13 = __

2. Sort the expressions into the correct group. Write each expression in the matching space.

   Expressions: 10 + 10, 18 + 2, 20 - 0, 15 + 4, 20 - 3, 9 + 9

   Equals 20:

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   Does not equal 20:

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Mission 4: Twenty in Real Life

1. A classroom has 20 pencils. Students use 6 pencils. How many pencils are left?

   Number sentence: ___

   Answer: __ pencils

2. Maya has 12 stickers. Her friend gives her 8 more. How many stickers does Maya have now?

   Number sentence: ___

   Answer: __ stickers

3. A baker puts 20 muffins on a tray. She sells 11 muffins. How many muffins remain?

   Number sentence: ___

   Answer: __ muffins

4. You have 20 cents. You spend 7 cents. How many cents do you have left?

   Number sentence: ___

   Answer: __ cents

5. Write or draw one way you could use the number 20 at home, school, or work.

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Mission 5: Think Deeper

1. There are 20 objects in a box. Some are red and some are blue. If 13 are red, how many are blue?

   Answer: __ blue objects

2. Find two different numbers that add to 20 and both are even.

   __ + __ = 20

3. Find two different numbers that add to 20 and both are odd.

   __ + __ = 20

4. I am a number between 15 and 20. I am greater than 17. What number could I be?

   Answer: __

5. Optional Challenge: Use three numbers to make 20. You may use addition, subtraction, or both.

   __ + __ + __ = 20

Reflection

1. Which activity helped you understand 20 best?

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2. What is one new way you learned to make 20?

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Answer Key

Mission 1

1. Answers should show five correctly written 20s.
2. 19
3. 21
4. 20, 20, 10 + 10
5. 19, 20, 21
6. 18, 17, 16, 15, 14

Mission 2

1. The drawing should contain 20 dots.
2. a. 10 b. 5 c. 13 d. 16
3. Answers may vary. Examples: 1 + 19, 2 + 18, 8 + 12
4. Answers may vary. Example: 25 - 5 = 20
5. a. greater than b. less than c. equal to

Mission 3

1. a. 20 b. 20 c. 15 d. 11 e. 20 f. 7

2. Equals 20: 10 + 10, 18 + 2, 20 - 0

   Does not equal 20: 15 + 4, 20 - 3, 9 + 9

Mission 4

1. 20 - 6 = 14; 14 pencils
2. 12 + 8 = 20; 20 stickers
3. 20 - 11 = 9; 9 muffins
4. 20 - 7 = 13; 13 cents
5. Answers will vary.

Mission 5

1. 7 blue objects
2. Answers may vary. Examples: 2 + 18, 4 + 16, 6 + 14
3. Answers may vary. Examples: 1 + 19, 3 + 17, 5 + 15
4. 18 or 19
5. Answers may vary. Example: 6 + 7 + 7 = 20

Reflection

Answers will vary.