Solved Exercises on Addition and Subtraction in Grade 2

Master addition and subtraction: basic operations, word problems, and problem-solving strategies through these 5 detailed exercises.

Solution: Exercises 1 to 3
1 Basic addition problem
Exercise 1: Basic Addition Problem

Solve this addition problem. Show your work!

Instructions: Read the problem carefully. Show your work in the space provided. Circle your final answer.
Addition method:
  1. Read the problem completely
  2. Identify the numbers to add
  3. Set up the equation
  4. Solve the equation
  5. Verify your answer
  6. Write the complete answer
Addition: 23 + 15 Addition
23 + 15 = ?
23
+
15
=
38
Step 1: Identify the numbers - We need to add 23 and 15
Step 2: Set up the equation - 23 + 15
Step 3: Add the ones place - 3 + 5 = 8
Step 4: Add the tens place - 20 + 10 = 30
Step 5: Combine the results - 30 + 8 = 38
Step 1: Identify the numbers

We need to add 23 and 15 together

Step 2: Add the ones place

3 + 5 = 8 (ones)

Step 3: Add the tens place

20 + 10 = 30 (tens)

Step 4: Combine the results

30 + 8 = 38

Step 5: Verify the answer

Check: 38 - 15 = 23 ✓

23 + 15 = 38
Final answer:

23 + 15 = 38

Applied rules:

• Place value addition: Add ones to ones, tens to tens

• Combining partial sums: Add the tens sum and ones sum

• Verification: Use subtraction to check addition

2 Basic subtraction problem
Exercise 2: Basic Subtraction Problem

Solve this subtraction problem. Show your work!

Definition:

Subtraction: Finding the difference between two numbers by taking one away from another.

Subtraction: 42 - 18 Subtraction
42 - 18 = ?
42
-
18
=
24
Step 1: Identify the numbers - Minuend is 42, subtrahend is 18
Step 2: Set up the equation - 42 - 18
Step 3: Subtract the ones place - 2 - 8 (need to borrow)
Step 4: Borrow from tens place - 12 - 8 = 4
Step 5: Subtract tens place - 3 - 1 = 2
Step 1: Identify the numbers

Minuend (top number) is 42, subtrahend (bottom number) is 18

Step 2: Look at the ones place

2 - 8: Since 2 < 8, we need to borrow from tens

Step 3: Borrow from tens place

Take 1 from 4 in tens place (making it 3), add 10 to ones place (making 2 into 12)

Step 4: Subtract the ones place

12 - 8 = 4

Step 5: Subtract the tens place

3 - 1 = 2

Step 6: Write the final answer

24

Step 7: Verify the answer

Check: 24 + 18 = 42 ✓

42 - 18 = 24
Final answer:

42 - 18 = 24

Applied rules:

• Borrowing rule: When top digit is smaller than bottom digit, borrow from next higher place value

• Place value subtraction: Subtract ones from ones, tens from tens

• Verification: Add the difference to the subtrahend to check

3 Mixed operations problem
Exercise 3: Mixed Operations Problem

Solve this problem with both addition and subtraction.

Definition:

Mixed operations: Problems that involve both addition and subtraction operations in sequence.

Mixed: 35 + 12 - 8 Addition Subtraction
35 + 12 - 8 = ?
35
+
12
-
8
=
39
Step 1: Perform addition first - 35 + 12 = 47
Step 2: Then perform subtraction - 47 - 8 = 39
Step 3: Write the final answer - 39
Step 1: Add first

35 + 12 = 47

Step 2: Subtract next

47 - 8 = 39

Step 3: Write the complete answer

35 + 12 - 8 = 39

Step 4: Verify the answer

Check: 39 + 8 - 12 = 35 ✓

35 + 12 - 8 = 39
Final answer:

35 + 12 - 8 = 39

Applied rules:

• Left-to-right order: Perform operations in the order they appear

• Sequential operations: Complete each operation before moving to the next

• Verification: Reverse operations to check the answer

Rules and methods, laws,...
Addition: A + B = C | Subtraction: A - B = C
Addition and Subtraction Formula
Addition
A + B = C
Combine numbers
Subtraction
A - B = C
Take away
Order of Operations
Left to Right
Sequential processing
Key definitions:

Addition: Finding the sum of two or more numbers by combining them.

Subtraction: Finding the difference between two numbers by taking one away from another.

Addend: Numbers being added together.

Sum: The result of addition.

Minuend: The number being subtracted from (the first number).

Subtrahend: The number being subtracted (the second number).

Difference: The result of subtraction (the answer).

Place value: The value of a digit based on its position (tens, ones).

Regrouping: Borrowing or carrying when a column sum reaches 10 or more.

Complete methodology:
  1. Read carefully: Read the entire problem to understand what is being asked
  2. Identify numbers: Find all the numbers mentioned in the problem
  3. Determine operation: Decide whether to add or subtract
  4. Set up equation: Write the mathematical equation
  5. Solve: Calculate the answer
  6. Verify: Check that your answer makes sense
  7. Write answer: Express the answer in the required format
Tip 1: Always align numbers by place value when doing column operations.
Tip 2: For subtraction, if the top digit is smaller, borrow from the next place value.
Tip 3: Add from right to left (ones, then tens).
Tip 4: Subtract from right to left (ones, then tens).
Tip 5: Always check your answer by using the inverse operation.
Tip 6: For mixed operations, work from left to right in the order shown.
Tip 7: Use mental math strategies for easier calculations.
Tip 8: Practice regularly to build speed and accuracy.
Common errors: Misaligning numbers, forgetting to borrow, adding instead of subtracting, subtracting instead of adding, miscalculating place values, not checking answers.
Key insight: Addition and subtraction are inverse operations - they undo each other.
Rules to remember:

• Place value alignment: Always align numbers by their place values

• Borrowing rule: When top digit < bottom digit in subtraction, borrow from next place value

• Order of operations: For mixed operations, work from left to right

• Verification: Check by using the inverse operation

• Regrouping: 1 ten = 10 ones, 1 hundred = 10 tens

Solution: Exercises 4 to 5
4 Word problem
Exercise 4: Word Problem

Solve this word problem. Show your work and write a complete answer.

Definition:

Word problem: A mathematical problem presented in everyday language requiring translation to numerical operations.

Word Problem: Sarah has 27 stickers. Her mom gives her 15 more stickers. Then Sarah gives 9 stickers to her friend. How many stickers does Sarah have now?
27 + 15 - 9 = ?
27
+
15
-
9
=
33
Step 1: Identify the numbers - Start with 27, get 15 more, give away 9
Step 2: Set up equation - 27 + 15 - 9
Step 3: Add first - 27 + 15 = 42
Step 4: Subtract next - 42 - 9 = 33
Step 5: Write complete answer - Sarah has 33 stickers
Step 1: Identify the numbers

Sarah starts with 27 stickers, gets 15 more, gives away 9

Step 2: Determine the operations

"Gets more" means addition, "gives" means subtraction

Step 3: Set up the equation

27 + 15 - 9 = 33

Step 4: Solve step by step

First: 27 + 15 = 42, Then: 42 - 9 = 33

Step 5: Write the complete answer

Sarah has 33 stickers now.

Step 6: Verify the answer

Check: 33 + 9 - 15 = 27 ✓

Sarah has 33 stickers now.
Final answer:

Sarah has 33 stickers now.

Applied rules:

• Sequential operations: Perform operations in the order they occur in the problem

• Contextual understanding: Translate words into mathematical operations

• Verification: Always check that your answer makes sense

5 Advanced mixed operations
Exercise 5: Advanced Mixed Operations

Solve this advanced problem with multiple operations.

Definition:

Advanced mixed operations: Problems with multiple addition and subtraction operations requiring careful sequence management.

Advanced Mixed: 48 - 15 + 12 - 7
48 - 15 + 12 - 7 = ?
48
-
15
+
12
-
7
=
38
Step 1: Start with 48
Step 2: Subtract 15 → 48 - 15 = 33
Step 3: Add 12 → 33 + 12 = 45
Step 4: Subtract 7 → 45 - 7 = 38
Step 5: Final answer is 38
Step 1: Start with 48

Begin with the first number in the sequence

Step 2: Subtract 15

48 - 15 = 33

Step 3: Add 12

33 + 12 = 45

Step 4: Subtract 7

45 - 7 = 38

Step 5: Write the final answer

48 - 15 + 12 - 7 = 38

Step 6: Verify the answer

Check: 38 + 7 - 12 + 15 = 48 ✓

48 - 15 + 12 - 7 = 38
Final answer:

48 - 15 + 12 - 7 = 38

Applied rules:

• Left-to-right sequence: Perform operations in order from left to right

• Step-by-step calculation: Complete each operation before moving to the next

• Verification: Reverse operations to confirm the answer

Complete Summary: Addition and Subtraction
A + B = C (where C is the sum) | A - B = C (where C is the difference)
Addition and Subtraction Formulas
Addition Summary

Definition: Combining numbers to find their total

Keywords: more, total, altogether, combined, sum

Process: Add ones to ones, tens to tens

Verification: Subtract one addend from sum

Subtraction Summary

Definition: Taking one number away from another

Keywords: less, left, gives, takes, away, remaining

Process: Subtract ones from ones, tens from tens

Verification: Add difference to subtrahend

Key definitions:

Addition: Combining two or more numbers to find their total.

Subtraction: Finding the difference between two numbers by taking one away from another.

Addend: The numbers being added together.

Sum: The result of addition.

Minuend: The number being subtracted from (the first number).

Subtrahend: The number being subtracted (the second number).

Difference: The result of subtraction (the answer).

Place value: The value of a digit based on its position (tens, ones).

Regrouping: Borrowing or carrying when necessary for operations.

Complete methodology:
  1. Read the problem: Understand what is being asked
  2. Identify numbers: Find all the numbers in the problem
  3. Determine operation: Decide whether to add or subtract
  4. Align numbers: Stack numbers by place value for column operations
  5. Perform operation: Add or subtract starting from the right
  6. Handle regrouping: Borrow or carry when necessary
  7. Write answer: Express the answer in the required format
  8. Verify: Check your answer using the inverse operation
Tip 1: Always align numbers by place value when doing column operations.
Tip 2: For subtraction, if the top digit is smaller, borrow from the next place value.
Tip 3: Add from right to left (ones, then tens).
Tip 4: Subtract from right to left (ones, then tens).
Tip 5: Always check your answer by using the inverse operation.
Tip 6: For mixed operations, work from left to right in the order shown.
Tip 7: Use mental math strategies for easier calculations.
Tip 8: Practice regularly to build speed and accuracy.
Tip 9: Draw pictures or use objects to visualize difficult problems.
Tip 10: Time yourself during practice to build test-taking skills.
Common errors: Misaligning numbers, forgetting to borrow, adding instead of subtracting, subtracting instead of adding, miscalculating place values, not checking answers, skipping steps, misreading the problem.
Key insight: Addition and subtraction are inverse operations - they undo each other, which is useful for checking answers.
Memory aid: Think "ASLR" - Add/Subtract from Left to Right for mixed operations.
Checking method: For addition, subtract one addend from the sum to get the other addend. For subtraction, add the difference to the subtrahend to get the minuend.
Rules to know by heart:

• Place value alignment: Always align numbers by their place values

• Borrowing rule: When subtracting and top digit < bottom digit, borrow from next place value

• Order of operations: For mixed operations, work from left to right

• Verification: Always check by using the inverse operation

• Regrouping: 1 ten = 10 ones, 1 hundred = 10 tens

• Direction: Both addition and subtraction start from the rightmost digit

• Keywords: "more", "total", "altogether" suggest addition; "less", "left", "gives" suggest subtraction

Multiple Examples

Basic addition: 23 + 15 = 38 (add ones: 3+5=8, add tens: 20+10=30, combine: 30+8=38)

Basic subtraction: 42 - 18 = 24 (borrow: 12-8=4, 3-1=2, answer: 24)

Mixed operations: 35 + 12 - 8 = 39 (first: 35+12=47, then: 47-8=39)

Advanced mixed: 48 - 15 + 12 - 7 = 38 (left to right: 48→33→45→38)

Word problem: "Sarah has 27, gets 15 more, gives away 9" → 27+15-9=33

Verification: 33 + 9 - 15 = 27 ✓

Questions & Answers

Question: When do I need to borrow in subtraction? It's confusing when the top number is smaller.

Answer: You need to borrow when the top digit in a column is smaller than the bottom digit in subtraction.

For example, in 42 - 18:

  • Look at ones place: 2 - 8
  • Since 2 is smaller than 8, you need to borrow
  • Take 1 from the tens place (4 becomes 3)
  • Add 10 to the ones place (2 becomes 12)
  • Now you can do 12 - 8 = 4
  • Then 3 - 1 = 2 in the tens place
  • Answer: 24

Think of it like exchanging money: if you need to pay 8 cents but only have 2 cents, you exchange 1 dime (10 cents) for 10 pennies, giving you 12 cents total.

Question: My child struggles with mixed operations like 25 + 13 - 8. How can I help them stay organized?

Answer: Mixed operations can be tricky! Here are strategies to help:

  1. Work left to right: Do operations in the order they appear
  2. Do one at a time: Complete the first operation before moving to the next
  3. Write intermediate steps: Show each calculation clearly
  4. Check progress: Verify each step before continuing

For 25 + 13 - 8:

  • First: 25 + 13 = 38
  • Then: 38 - 8 = 30
  • Final answer: 30

You can also use different colored pencils for each step to help visualize the process.

Question: How can I check if my answer is correct after solving an addition or subtraction problem?

Answer: There are two good ways to check your answer:

  1. Use the inverse operation: If you added, check by subtracting. If you subtracted, check by adding.
  2. Estimate: See if your answer makes sense compared to the original numbers.

Examples:

  • If you calculated 23 + 15 = 38, check by doing 38 - 15 = 23 ✓
  • If you calculated 42 - 18 = 24, check by doing 24 + 18 = 42 ✓

You can also do a quick mental check: Does the answer make sense? If I add 23 and 15, should I get a number around 38? Yes, because 20 + 15 = 35, and 3 more gives 38.

Checking your work is an important habit that will help you catch mistakes early!