6th Grade Mathematics — Ratios and Proportions — God's Mathematical Design
Understanding Parts per Hundred and Their Applications
A percentage (or percent) is a ratio that compares a number to 100. The word 'percent' comes from the Latin 'per centum,' meaning 'per hundred.' When we say 25%, we mean 25 out of 100, or 25/100. Percentages give us a standardized way to express parts of a whole, making it easy to compare different quantities.
Percentages are used everywhere: in shopping (20% off sale), banking (3% interest rate), grades (scored 85%), sports (free-throw percentage of 75%), and nutrition (10% of daily value). Understanding percentages is essential for making wise decisions about money, health, and many other areas of life.
Fractions, decimals, and percentages are three different ways of expressing the same value. To convert a fraction to a percent, divide the numerator by the denominator and multiply by 100. For example, 3/4 = 0.75 = 75%. To convert a decimal to a percent, multiply by 100 (move the decimal point two places to the right). For example, 0.35 = 35%.
To convert a percent to a decimal, divide by 100 (move the decimal point two places to the left). For example, 42% = 0.42. To convert a percent to a fraction, write the percent over 100 and simplify. For example, 60% = 60/100 = 3/5. Being able to move fluently between these three forms is a critical math skill.
To find a percentage of a number, convert the percent to a decimal and multiply. For example, what is 15% of 200? Convert 15% to 0.15, then multiply: 0.15 × 200 = 30. So 15% of 200 is 30.
This skill has many practical applications. If a $50 item is 20% off, the discount is 0.20 × $50 = $10, so the sale price is $40. If you earn $500 and want to tithe 10%, you would give 0.10 × $500 = $50. Being able to calculate percentages quickly helps you make informed decisions every day.
The tithe is one of the oldest and most well-known examples of a percentage in the Bible. Abraham gave a tithe — 10% — to Melchizedek (Genesis 14:20). Later, God commanded the Israelites to tithe to support the Levites, the priests, and the poor (Leviticus 27:30, Deuteronomy 14:28-29).
The principle of the tithe teaches us something important about percentages and proportional thinking: the amount you give is proportional to what you have received. A person who earns $1,000 per month would tithe $100. A person who earns $5,000 would tithe $500. The percentage stays the same, but the amount adjusts to the person's income. This proportional approach to giving is fair, generous, and built on the mathematical concept of percentages.
Write thoughtful responses to the following questions. Use evidence from the lesson text, Scripture references, and primary sources to support your answers.
Why do you think God chose a percentage (10%) for the tithe rather than a fixed dollar amount? How does proportional giving reflect God's fairness?
Guidance: Consider that a fixed amount would be easy for the wealthy but hard for the poor. Think about how a percentage-based approach adjusts to each person's ability.
A store advertises '30% off everything.' If a jacket costs $80, what is the sale price? Show your work and explain each step.
Guidance: Calculate the discount: 0.30 × $80 = $24. Subtract from the original price: $80 - $24 = $56. Explain why you convert the percent to a decimal before multiplying.
How does understanding percentages help you be a better steward of your money? Give examples of how you might use percentage calculations in your daily life.
Guidance: Think about budgeting (allocating percentages to saving, giving, and spending), understanding sales, calculating tips, and evaluating financial decisions.