This is Part 1 of my Percentage Series, where we’ll focus on finding the part of a total. This skill is essential for solving real-world math problems, like discounts, test scores, and data analysis.
I’ll walk you through two different methods to solve percent-of problems:
- Changing the percent to a decimal and multiplying
- Using proportions
Let’s get started!
Example Problem: What is 16% of 70?
We’re going to solve this problem two different ways and check that we get the same answer.
Method 1: Change Percent to Decimal and Multiply
The word “of” in math usually means multiply. That’s our first clue.
- Start with the percentage: 16%.
- To convert a percent to a decimal, move the decimal point two places to the left.
- 16% → 0.16
- Multiply the decimal by the total: 0.16×70=11.2
✅ Final Answer: 16% of 70 = 11.2
Method 2: Solve with Proportions
This method works for all types of percent problems—whether you’re finding the part, the total, or the percentage.
We set up the proportion like this: Percent/100=Part/Total
Now plug in the numbers: 16/100=x/70
- Cross multiply: 100x=1120
- Divide both sides by 100: x=11.2
✅ Final Answer: 16% of 70 = 11.2
Does the Answer Make Sense?
Always double-check if your answer is reasonable.
- Since 16% is less than 20%, the answer should be less than 20% of 70.
- 20% of 70 = 14. So our answer, 11.2, makes perfect sense.
- If you had mistakenly written 112 or 1.12, those would not make sense—one is too large, and one is too small compared to the total.
Key Takeaways
- Method 1 (Decimal Method): Change percent to decimal and multiply by the total.
- Method 2 (Proportions): Set up percent/100=part/total and solve.
- Always ask yourself: Does this answer make sense compared to the total?
More Percentage Lessons
This is just Part 1 of my Percentage Series. Be sure to check out the next lessons:
- Part 2: Finding the Total from the Part and the Percentage
- Part 3: Finding the Percentage from the Part and the Total
These videos are all part of my Pre-Algebra Math Series, which covers the essential skills you’ll need for middle school math and beyond.
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