Learning Objectives
- Practise addition and subtraction with larger numbers
- Solve word problems related to daily life
- Understand the connection between addition and subtraction
- Count and calculate with numbers up to 50
- Build confidence in solving simple maths problems
Key Concepts
Addition with Bigger Numbers
Now we can add numbers that give sums up to 50. For example, 12 + 5 = 17. We can also add: 20 + 10 = 30, 15 + 15 = 30, 25 + 13 = 38. We start from the first number and count forward by the second number.
Subtraction with Bigger Numbers
We can subtract bigger numbers too. For example, 18 − 5 = 13. We can also do: 30 − 10 = 20, 45 − 20 = 25, 36 − 14 = 22. We start from the bigger number and count backward.
Word Problems
Word problems tell a story using numbers. For example: Riya has 12 toffees. Her mother gives her 8 more. How many toffees does Riya have now? We add: 12 + 8 = 20. Riya has 20 toffees. Read the problem carefully to decide if you need to add or subtract.
When to Add and When to Subtract
We add when we get more, combine, or put together. Words like "in all", "total", "altogether", and "more" tell us to add. We subtract when things are taken away, lost, or given away. Words like "left", "remaining", "less", and "how many more" tell us to subtract.
Checking Our Answers
After solving a problem, we can check our answer. If we added 14 + 6 = 20, we can check by subtracting: 20 − 6 = 14. If we get back the first number, our answer is correct.
Important Terms
- Word problem: A maths question written as a short story
- Altogether: A word that tells us to add all the amounts together
- Remaining: What is left after taking away some amount
- How many more: Finding the difference between two amounts by subtracting
Quick Revision
- We can now add and subtract numbers up to 50
- Read word problems carefully to find the key information
- Words like "total" and "altogether" mean addition
- Words like "left" and "remaining" mean subtraction
- Check your answer using the opposite operation
- Practice: 23 + 15 = 38, 40 − 18 = 22, 27 + 13 = 40