Addition Within 100

Grade 2 · mathematics · 100 practice problems · read aloud

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Addition Within 100

Addition is like putting groups of things together to find the total. We use it all the time, like when counting toys, adding up points in a game, or sharing snacks with friends!

How to Add (Step-by-Step)

  1. Write it down: Write the problem with one number on top of the other. Make sure the ones and tens places line up!
  2. Add the Ones place first: Start with the column on the far right.
  3. Add the Tens place: Move to the column on the left and add those numbers.
  4. Write the total: The number you get is your answer!

Let's Try Some Examples! ✏️

Example 1: 24 + 35

Step 1: Add the Ones: 4 + 5 = 9

Step 2: Add the Tens: 2 + 3 = 5

Answer: 59

Example 2: 47 + 28

Step 1: Add the Ones: 7 + 8 = 15. Write down the 5 in the Ones place, and carry the 1 (a ten) to the Tens column.

Step 2: Add the Tens: 1 + 4 + 2 = 7

Answer: 75

Watch Out! Common Mistakes

Mixing up place value: Always make sure the Ones and Tens are lined up! Adding 23 + 4 is not 27 if you write it as 234.

Forgetting to carry: When the Ones add up to 10 or more, don't forget to carry the extra ten over!

Tips & Tricks 🧠

  • Doubles are your friend: Remember doubles like 5+5=10 and 8+8=16. They make adding faster!
  • Make a ten: If you see 8 + 5, think "8 needs 2 to make 10." Take 2 from the 5 to make 10, then add the leftover 3 to get 13.
  • Draw it: Draw tens as sticks (| |) and ones as dots (• •) to help you see the problem.

How to Get Better

The best way to become an addition expert is to practice!

  • Use flashcards.
  • Play online math games.
  • Ask a family member to give you quick problems to solve.
  • Look for addition problems in your day, like adding up the number of apples in two bags.

Practice problems

6 of the 100, worked through step by step — try them before opening the answer.

1 99 + 1 = ?

Hint: Add the ones first, then the tens, carrying if needed.

Show the answer

Answer: 100

  1. Start with 99.
  2. Add 1: 99 + 1 = 100.

The answer is 100.

2 9 + 24 = ?

Hint: Add the ones first, then the tens, carrying if needed.

Show the answer

Answer: 33

  1. Start with 9.
  2. Add 24: 9 + 24 = 33.

The answer is 33.

3 62 + 3 = ?

Hint: Add the ones first, then the tens, carrying if needed.

Show the answer

Answer: 65

  1. Start with 62.
  2. Add 3: 62 + 3 = 65.

The answer is 65.

4 47 + 28 = ?

Hint: When adding two numbers, start with the ones place and remember to carry over if needed.

Show the answer

Answer: 75

  1. Write the numbers vertically in your mind (or on paper) to align the place values: 47 + 28
  2. Start by adding the digits in the ones column (rightmost column): 7 + 8. 7 + 8 = 15
  3. Since 15 is a two-digit number, we separate it into 10 (which is 1 ten) and 5 (ones). Write down the 5 in the ones place of the answer, and carry over the 1 ten to the tens column.
  4. Now add the digits in the tens column, including the carry-over: The tens column has 4 (from 47) + 2 (from 28) + 1 (carried over) = 4 + 2 + 1 = 7.
  5. Combine the tens and ones results: 7 tens and 5 ones gives 75. So, 47 + 28 = 75.

Let's add 47 and 28 step by step.

5 47 + 36 = ?

Hint: Think about adding the tens first, then the ones, and combining them.

Show the answer

Answer: 83

  1. Write the numbers vertically in your mind, aligning them by place value (ones and tens). 47 + 36
  2. Add the digits in the ones column first: 7 + 6. 7 + 6 = 13
  3. Since 13 is a two-digit number, we separate it into 10 (1 ten) and 3 (3 ones). Write down the 3 in the ones place of the answer, and carry over the 1 (which is 1 ten) to the tens column.
  4. Now add the digits in the tens column, including the carried-over 1. 4 (from 47) + 3 (from 36) + 1 (carried over) = 8
  5. Write the 8 in the tens place of the answer.
  6. Combine the tens and ones digits: 8 tens and 3 ones makes 83. Final answer: 83

Let's add 47 and 36 step by step.

6 45 + 28 = ?

Hint: Add the ones place first, then the tens place. Remember to regroup if needed.

Show the answer

Answer: 73

  1. Write the numbers vertically in your mind, aligning them by place value. 45 + 28
  2. Start by adding the digits in the ones place. 5 (from 45) + 8 (from 28) = 13.
  3. Since 13 is a two-digit number, we separate it into 10 and 3. Write down the 3 in the ones place of the answer, and carry over the 10 (which is 1 ten) to the tens place.
  4. Now add the digits in the tens place, including the carried-over ten. 4 (from 45) + 2 (from 28) + 1 (carried over) = 7.
  5. Write the 7 in the tens place of the answer.
  6. Combine the tens and ones digits: 7 tens and 3 ones makes 73. Therefore, 45 + 28 = 73.

Let's add 45 and 28 step by step.

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