Math Antics - Finding A Percent Of A Number

Summary

In this Math Antics video, the focus is on understanding how to find a percent of a number. The host explains that a percent represents a fraction, and finding a percent of a number is essentially calculating a fraction of that amount. Through engaging examples, viewers learn two methods: using the fraction form or decimal form of a percent to multiply it by the number in question. The video also covers real-life applications, such as determining how much money you earn based on a percentage or figuring out how many students are at school with a 120% increase. The key takeaway is that practice makes perfect when it comes to mastering this essential skill.

Takeaways

• 😀 Finding a percent of a number means calculating a fraction of that number.
• 😀 A percent is just a fraction, and finding a percent of a number is the same as finding a fraction of an amount.
• 😀 When dealing with percents, 'of' is equivalent to multiplication (e.g., 25% of 20 = 25% × 20).
• 😀 To multiply a percent and a number, you must convert the percent into either a fraction or decimal form first.
• 😀 25% is equivalent to the fraction 25/100 or the decimal 0.25.
• 😀 To find 25% of 20, multiply 25/100 by 20, which simplifies to 5.
• 😀 Alternatively, you can use the decimal form of a percent (e.g., 0.25) and multiply it by the number to get the same result.
• 😀 Using a calculator makes the process faster, but it’s also important to understand the underlying math.
• 😀 When finding a percent of a number, the result is often smaller than the original number (e.g., 25% of 20 = 5).
• 😀 A percent can also be greater than 100%, meaning you could end up with a larger number (e.g., 120% of 400 = 480).

Q & A

What does finding a percent of a number really mean?

Finding a percent of a number means finding a fraction of the total amount. Essentially, it's calculating what portion of the number the given percentage represents.

How do we find 25% of 20 ladybugs in the example provided?

To find 25% of 20, you multiply 25% by 20. First, convert 25% into a fraction (25/100) and multiply it by 20 (as a fraction 20/1), then simplify the result to find that 25% of 20 is 5.

Why can't we just multiply the percent sign by the number directly?

If we multiplied the percent and the number directly, without converting the percent to a fraction or decimal, the result would be too large. For example, multiplying 25 and 20 directly would give us 500, which is incorrect.

What happens when we convert a percent to a fraction?

When a percent is written as a fraction, we convert the percent by placing it over 100. For example, 25% becomes 25/100. This allows us to correctly multiply by the amount and simplify to get the correct result.

What is the difference between using a fraction and a decimal to find a percent of a number?

Both methods give the same result, but using the decimal form may be more convenient, especially if you're using a calculator. For instance, 25% can be written as 0.25 in decimal form, which simplifies the multiplication.

How do you convert a percent to its decimal form?

To convert a percent to decimal form, move the decimal point two places to the left. For example, 25% becomes 0.25.

What would be the result if you calculated 35% of $80?

To find 35% of $80, you multiply 0.35 (the decimal form of 35%) by 80, which equals $28. This is the amount you would get if you helped your friend walk dogs.

How do you calculate more than 100% of a number?

To calculate more than 100% of a number, you use the decimal form of the percentage greater than 1. For example, 120% is 1.20 in decimal form. Then, you multiply 1.20 by the total amount (e.g., 400 students), resulting in 480 students.

Why is the example of 120% of 400 students used?

The example of 120% of 400 students shows that percents can be greater than 100%. In this case, 120% means an increase in the total, so you multiply 400 by 1.20 to find that there are 480 students this year.

What is the most important concept to remember when calculating a percent of a number?

The most important concept is that a percent is a fraction, and you can find the percent of a number by multiplying the number by the fraction or decimal form of the percent.