Reciprocal facts for kids
The reciprocal of a number is what you get when you divide 1 by that number. It's also called the multiplicative inverse. Think of it like this: if you multiply a number by its reciprocal, the answer will always be 1.
For example:
- If you have the number 2, its reciprocal is 1/2 (or 0.5). Why? Because 2 multiplied by 0.5 equals 1.
- If you have 0.25, its reciprocal is 4. Why? Because 0.25 multiplied by 4 equals 1.
Every number has a reciprocal, except for zero. You can't find a reciprocal for zero because nothing multiplied by zero equals one.
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Finding Reciprocals
It's easy to find the reciprocal of different types of numbers.
For Whole Numbers and Decimals
To find the reciprocal of a whole number, just put 1 over that number. For example, the reciprocal of 8 is 1/8.
For decimals, you can often convert them to fractions first, or simply divide 1 by the decimal.
- The reciprocal of 2.5 is 1 divided by 2.5, which is 0.4.
- The reciprocal of -0.2 is 1 divided by -0.2, which is -5.
Some numbers are their own reciprocals!
- The reciprocal of 1 is 1, because 1 × 1 = 1.
- The reciprocal of -1 is -1, because -1 × -1 = 1.
For Fractions
Finding the reciprocal of a fraction is super simple! All you need to do is flip the fraction upside down. This means the top number (numerator) becomes the bottom number (denominator), and the bottom number becomes the top number.
- The reciprocal of 5/3 is 3/5.
- The reciprocal of 1/7 is 7/1, which is just 7.
- The reciprocal of -9/4 is -4/9.
Reciprocals and Division
Reciprocals are very useful when you are dividing fractions. When you divide by a fraction, it's the same as multiplying by its reciprocal.
For example, if you want to calculate 1/2 divided by 1/4: 1. Find the reciprocal of the second fraction (1/4), which is 4/1 (or 4). 2. Change the division problem into a multiplication problem: 1/2 multiplied by 4. 3. The answer is 2.
This trick makes dividing fractions much easier!
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