What is 15 + 5?

S1-SA1-1202

Grade Level:

Class 1

Maths, Computing, AI

Definition

What is it?

15 + 5 is an addition problem where you combine the number 15 with the number 5. Addition means finding the total when you put two or more numbers together.

Simple Example

Quick Example

Imagine you have 15 ladoos in one box. Your friend gives you 5 more ladoos. To find out how many ladoos you have in total, you would do 15 + 5.

Worked Example

Step-by-Step

Let's calculate 15 + 5:

Step 1: Start with the first number, 15.
---
Step 2: Now, we need to add 5 to it. You can count forward 5 times from 15.
---
Step 3: Count: 16 (1st count), 17 (2nd count), 18 (3rd count), 19 (4th count), 20 (5th count).
---
Step 4: After counting 5 steps forward from 15, you reach 20.
---
So, 15 + 5 = 20.

Why It Matters

Understanding addition is super important for many things! In Maths, it's the base for all other operations. In Computing, basic addition is used in every program, from calculating game scores to managing data. Even AI uses addition to process information and make decisions, like in self-driving cars or smart assistants. You'll use it in careers like software development, data analysis, and even finance.

Common Mistakes

MISTAKE: Students sometimes count one number short or extra. For example, counting 15, 16, 17, 18, 19 and stopping at 19 instead of 20. | CORRECTION: Always double-check your counting. Start from the number after the first number (15, so start counting from 16) and count exactly the second number of times (5 times).

MISTAKE: Confusing addition with subtraction. For example, doing 15 - 5 instead of 15 + 5. | CORRECTION: Remember that '+' means 'add' or 'put together', and '-' means 'take away'. Look carefully at the symbol between the numbers.

MISTAKE: Not understanding place value when numbers get bigger. For example, if it was 15 + 7, some might try to add 5 and 7 and then ignore the 1 in 15. | CORRECTION: For simple addition like 15+5, you can count forward. For larger numbers, remember to add the ones place first, then the tens place, carrying over if needed.

Practice Questions

Try It Yourself

QUESTION: You have 12 cricket bats. Your coach gives you 8 more bats. How many bats do you have in total? | ANSWER: 20 bats

QUESTION: A bus has 17 passengers. At the next stop, 3 more passengers get on. How many passengers are now on the bus? | ANSWER: 20 passengers

QUESTION: Priya bought a comic book for Rs 15 and a packet of chips for Rs 5. She also bought a pen for Rs 10. How much money did she spend in total on the comic book and chips? | ANSWER: Rs 20

MCQ

Quick Quiz

Which of these shows the correct answer for 15 + 5?

The Correct Answer Is:

When you add 15 and 5, you are combining them. Counting 5 steps forward from 15 (16, 17, 18, 19, 20) leads to 20. Options A, C, and D are incorrect as they represent subtraction, one of the original numbers, or the number being added, not the sum.

Real World Connection

In the Real World

You use addition every day! When you're checking your mobile data usage, you might add up how many MBs you used in the morning and evening. When you're buying groceries, the shopkeeper adds up the prices of different items using a billing machine, which uses basic addition. Even cricket analysts add up runs scored by different batsmen to calculate total team scores.

Key Vocabulary

Key Terms

ADDITION: The process of combining numbers to find their total | SUM: The result you get when you add two or more numbers together | PLUS SIGN: The '+' symbol, which means to add | TOTAL: The final amount after adding numbers

What's Next

What to Learn Next

Great job with addition! Next, you can learn about 'What is 20 - 5?'. Subtraction is the opposite of addition and helps you find out how much is left after taking some away, which is another super useful skill!