What is The Number 71?

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Grade Level:

Pre-School – Class 2

All domains without exception

Definition

What is it?

The number 71 is a natural number that comes after 70 and before 72. It is an odd number because it cannot be divided equally by 2, and it is also a prime number, meaning it can only be divided by 1 and itself.

Simple Example

Quick Example

Imagine your favourite cricket team scored 70 runs. If they score one more run, their total score will become 71 runs. This is how 71 fits into counting after 70.

Worked Example

Step-by-Step

Let's find out if 71 is a prime number.

1. A prime number is a number greater than 1 that has only two factors: 1 and itself.
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2. Let's try to divide 71 by small prime numbers like 2, 3, 5, 7, 11, and so on.
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3. Divide 71 by 2: 71 ÷ 2 = 35 with a remainder of 1. So, 2 is not a factor.
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4. Divide 71 by 3: 7 + 1 = 8. Since 8 is not divisible by 3, 71 is not divisible by 3.
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5. Divide 71 by 5: Numbers divisible by 5 end in 0 or 5. 71 does not end in 0 or 5. So, 5 is not a factor.
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6. Divide 71 by 7: 71 ÷ 7 = 10 with a remainder of 1. So, 7 is not a factor.
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7. We only need to check prime factors up to the square root of 71, which is about 8.4. Since we've checked 2, 3, 5, and 7, and none divide 71 evenly.
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8. This means 71 has no factors other than 1 and 71.

Answer: Yes, 71 is a prime number.

Why It Matters

Understanding numbers like 71 helps build a strong foundation for all maths. It's crucial for careers in data science where you work with large datasets, or in finance where you deal with exact figures. Even engineers use numbers constantly to design and build things.

Common Mistakes

MISTAKE: Thinking 71 is an even number because it has a 7 in it. | CORRECTION: An even number is always divisible by 2. Since 71 leaves a remainder of 1 when divided by 2, it is an odd number.

MISTAKE: Confusing 71 with 17. | CORRECTION: 71 and 17 are different numbers. 71 has 7 tens and 1 one, while 17 has 1 ten and 7 ones. Their values are completely different.

MISTAKE: Believing 71 has many factors. | CORRECTION: 71 is a prime number, which means its only factors are 1 and 71 itself. It cannot be divided evenly by any other number.

Practice Questions

Try It Yourself

QUESTION: What number comes just before 71? | ANSWER: 70

QUESTION: If you have 70 marbles and your friend gives you 1 more, how many marbles do you have in total? | ANSWER: 71 marbles

QUESTION: Is 71 a prime number or a composite number? Explain why. | ANSWER: 71 is a prime number because it only has two factors: 1 and 71.

MCQ

Quick Quiz

Which of the following statements about the number 71 is true?

It is an even number.

It is divisible by 3.

It is a prime number.

It is greater than 100.

The Correct Answer Is:

71 is an odd number, so A is false. The sum of its digits (7+1=8) is not divisible by 3, so B is false. 71 is less than 100, so D is false. 71 is a prime number because its only factors are 1 and 71.

Real World Connection

In the Real World

Imagine you are tracking how many deliveries a Zepto rider completes in an hour. If they complete 71 deliveries, that specific number represents a count. Similarly, in a game of Ludo, you might need to move your token exactly 71 steps to reach home, using a combination of dice rolls.

Key Vocabulary

Key Terms

NATURAL NUMBER: A counting number starting from 1 (1, 2, 3,...). | ODD NUMBER: A number that cannot be divided exactly by 2, leaving a remainder of 1. | PRIME NUMBER: A whole number greater than 1 that has exactly two factors: 1 and itself. | FACTOR: A number that divides another number exactly, without leaving a remainder.

What's Next

What to Learn Next

Now that you understand what 71 is, you can explore other types of numbers like composite numbers or perfect numbers. This will help you see how numbers are categorised and understand their unique properties.