Addition and Subtraction
Standard 2 Mathematics: Addition and Subtraction
Place value up to tens, addition up to 50, subtraction from 50 and reverse operations.
➕➖🔢
Welcome to Standard 2 Addition and Subtraction!
Today we will add and subtract numbers up to 50.
In this lesson, we will use tens and ones to understand numbers. Then we will add, subtract, and see how subtraction can reverse addition.
Identify place value up to tens.
Add whole numbers with sums up to 50.
Subtract whole numbers from 50 without decomposition.
Relate addition to subtraction.
🌟 Complete the missions and become an Addition and Subtraction Champion!
Teaching: Tens and Ones
Place value helps us know the value of each digit in a number.
A ten is a group of 10 ones. In the number 34, the 3 means 3 tens and the 4 means 4 ones.
Tens
Ones
34 = 3 tens and 4 ones
Interactive Place Value Builder
Build a number by adding tens and ones.
Number: 0
Tens
Ones
Build numbers up to 50.
Activity: Identify Place Value
In 42, what does the 4 stand for?
42 = 4 tens and 2 ones
4 tens
4 ones
2 tens
Teaching: Adding Whole Numbers up to 50
Addition means putting numbers together to find the total.
To add 23 + 14, add the tens and ones. 2 tens plus 1 ten is 3 tens. 3 ones plus 4 ones is 7 ones. So 23 + 14 = 37.
23
2 tens and 3 ones
+ 14
1 ten and 4 ones
= 37
3 tens and 7 ones
Activity: Add Whole Numbers
Add the numbers. The sum is not more than 50.
24 + 15 = ?
29
39
49
Activity: Type the Addition Answer
Type the answer for 31 plus 8.
31 + 8 = ?
Teaching: Subtracting Without Decomposition
Subtraction means taking away.
Without decomposition means we do not need to borrow. For example, 48 - 16 is easy because 8 ones can take away 6 ones.
48
4 tens and 8 ones
- 16
take away 1 ten and 6 ones
= 32
3 tens and 2 ones
Activity: Subtract Whole Numbers
Subtract without borrowing.
47 - 23 = ?
24
34
20
Activity: Type the Subtraction Answer
Type the answer for 50 minus 20.
50 - 20 = ?
Teaching: Addition and Subtraction are Related
Subtraction can reverse addition.
If 20 + 15 = 35, then 35 - 15 = 20. Subtraction takes us back to where we started.
20 + 15 = 35
Addition puts together.
↔
Reverse
35 - 15 = 20
Subtraction takes away.
Activity: Reverse the Addition
If 18 + 12 = 30, what is 30 - 12?
18 + 12 = 30
30 - 12 = ?
18
12
42
Mixed Practice
Choose the correct answer.
36 + 10 = ?
26
46
50
Addition and Subtraction Quiz
1. In 35, the 3 means:
2. 22 + 16 =
3. 49 - 24 =
4. If 30 + 10 = 40, then 40 - 10 =
5. 50 - 30 =
🎉➕➖
Great Job, Maths Champion!
You identified tens and ones.
You added whole numbers with sums up to 50.
You subtracted whole numbers from 50 without decomposition.
You learned that subtraction reverses addition.
🌟 You are ready for more Standard 2 number work!
Standard 2 Mathematics: Addition and Subtraction
Place value up to tens, addition up to 50, subtraction from 50 and reverse operations.
➕➖🔢
Welcome to Standard 2 Addition and Subtraction!
Today we will add and subtract numbers up to 50.
In this lesson, we will use tens and ones to understand numbers. Then we will add, subtract, and see how subtraction can reverse addition.
Identify place value up to tens.
Add whole numbers with sums up to 50.
Subtract whole numbers from 50 without decomposition.
Relate addition to subtraction.
🌟 Complete the missions and become an Addition and Subtraction Champion!
Teaching: Tens and Ones
Place value helps us know the value of each digit in a number.
A ten is a group of 10 ones. In the number 34, the 3 means 3 tens and the 4 means 4 ones.
Tens
Ones
34 = 3 tens and 4 ones
Interactive Place Value Builder
Build a number by adding tens and ones.
Number: 0
Tens
Ones
Build numbers up to 50.
Activity: Identify Place Value
In 42, what does the 4 stand for?
42 = 4 tens and 2 ones
4 tens
4 ones
2 tens
Teaching: Adding Whole Numbers up to 50
Addition means putting numbers together to find the total.
To add 23 + 14, add the tens and ones. 2 tens plus 1 ten is 3 tens. 3 ones plus 4 ones is 7 ones. So 23 + 14 = 37.
23
2 tens and 3 ones
+ 14
1 ten and 4 ones
= 37
3 tens and 7 ones
Activity: Add Whole Numbers
Add the numbers. The sum is not more than 50.
24 + 15 = ?
29
39
49
Activity: Type the Addition Answer
Type the answer for 31 plus 8.
31 + 8 = ?
Teaching: Subtracting Without Decomposition
Subtraction means taking away.
Without decomposition means we do not need to borrow. For example, 48 - 16 is easy because 8 ones can take away 6 ones.
48
4 tens and 8 ones
- 16
take away 1 ten and 6 ones
= 32
3 tens and 2 ones
Activity: Subtract Whole Numbers
Subtract without borrowing.
47 - 23 = ?
24
34
20
Activity: Type the Subtraction Answer
Type the answer for 50 minus 20.
50 - 20 = ?
Teaching: Addition and Subtraction are Related
Subtraction can reverse addition.
If 20 + 15 = 35, then 35 - 15 = 20. Subtraction takes us back to where we started.
20 + 15 = 35
Addition puts together.
↔
Reverse
35 - 15 = 20
Subtraction takes away.
Activity: Reverse the Addition
If 18 + 12 = 30, what is 30 - 12?
18 + 12 = 30
30 - 12 = ?
18
12
42
Mixed Practice
Choose the correct answer.
36 + 10 = ?
26
46
50
Addition and Subtraction Quiz
1. In 35, the 3 means:
2. 22 + 16 =
3. 49 - 24 =
4. If 30 + 10 = 40, then 40 - 10 =
5. 50 - 30 =
🎉➕➖
Great Job, Maths Champion!
You identified tens and ones.
You added whole numbers with sums up to 50.
You subtracted whole numbers from 50 without decomposition.
You learned that subtraction reverses addition.
🌟 You are ready for more Standard 2 number work!
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