In this Grade 8 lesson from Saxon Math, Course 3, students learn how to define and write ratios as comparisons of two numbers by division, expressing them in four forms: using the word "to," as a fraction, as a decimal, and with a colon. The lesson covers reducing ratios, distinguishing ratios from rates, and estimating approximate ratios by rounding. Students apply these skills through real-world contexts such as comparing groups of people, shadow lengths, and calculating reading rates in pages per minute.
Section 1
📘 Ratio
A ratio is a comparison of two numbers by division. Ratios can be written with the word to (3 to 4), as a fraction (), as a decimal (), or with a colon ().
Next, you'll solve problems that involve writing, simplifying, and estimating ratios in various real-world scenarios, including calculating rates from data.
Section 2
What Is A Ratio?
A ratio is a comparison of two numbers by division. It can be written with the word 'to' (3 to 4), as a fraction (), as a decimal (0.75), or with a colon (3:4).
In a class with 12 girls and 16 boys, the ratio of girls to boys is .
A bag has 6 red marbles and 8 blue ones; the ratio of red to blue is .
The ratio 5 to 2 can also be written as or as the fraction .
Think of a ratio as a recipe for comparing things! It shows how much of one item you have for every certain amount of another. It helps simplify relationships, like comparing 12 girls to 16 boys by just saying it’s a 3 to 4 ratio.
Section 3
Thinking Skill: Represent
In some situations, we round numbers to express a ratio. For example, .
1217 home fans and 897 visiting fans is approximated as , which simplifies to a ratio.
If a company sells 1,988 widgets and 1,012 gadgets, the ratio is roughly , or 2 to 1.
When real-world numbers get messy, just round them off! This turns complicated figures like 789 and 597 into simple, friendly numbers like 800 and 600. It lets you create an approximate ratio that’s much easier to understand and compare, like saying it's about 4 to 3.
Section 4
Order In Ratios
Always write the ratio in the order stated. The ratio of A to B is , while the ratio of B to A is .
With 15 boys and 9 girls, the ratio of boys to girls is .
With 15 boys and 9 girls, the ratio of girls to boys is .
A 20 ft flagpole with a 24 ft shadow has a height-to-shadow ratio of .
Order is the boss! The ratio of 'boys to girls' is completely different from 'girls to boys.' Always read the problem carefully to see which item comes first, and write your fraction in that same sequence. Getting it backward will flip your answer upside down!
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Section 1
📘 Ratio
A ratio is a comparison of two numbers by division. Ratios can be written with the word to (3 to 4), as a fraction (), as a decimal (), or with a colon ().
Next, you'll solve problems that involve writing, simplifying, and estimating ratios in various real-world scenarios, including calculating rates from data.
Section 2
What Is A Ratio?
A ratio is a comparison of two numbers by division. It can be written with the word 'to' (3 to 4), as a fraction (), as a decimal (0.75), or with a colon (3:4).
In a class with 12 girls and 16 boys, the ratio of girls to boys is .
A bag has 6 red marbles and 8 blue ones; the ratio of red to blue is .
The ratio 5 to 2 can also be written as or as the fraction .
Think of a ratio as a recipe for comparing things! It shows how much of one item you have for every certain amount of another. It helps simplify relationships, like comparing 12 girls to 16 boys by just saying it’s a 3 to 4 ratio.
Section 3
Thinking Skill: Represent
In some situations, we round numbers to express a ratio. For example, .
1217 home fans and 897 visiting fans is approximated as , which simplifies to a ratio.
If a company sells 1,988 widgets and 1,012 gadgets, the ratio is roughly , or 2 to 1.
When real-world numbers get messy, just round them off! This turns complicated figures like 789 and 597 into simple, friendly numbers like 800 and 600. It lets you create an approximate ratio that’s much easier to understand and compare, like saying it's about 4 to 3.
Section 4
Order In Ratios
Always write the ratio in the order stated. The ratio of A to B is , while the ratio of B to A is .
With 15 boys and 9 girls, the ratio of boys to girls is .
With 15 boys and 9 girls, the ratio of girls to boys is .
A 20 ft flagpole with a 24 ft shadow has a height-to-shadow ratio of .
Order is the boss! The ratio of 'boys to girls' is completely different from 'girls to boys.' Always read the problem carefully to see which item comes first, and write your fraction in that same sequence. Getting it backward will flip your answer upside down!
Book overview
Jump across lessons in the current chapter without opening the full course modal.
Continue this chapter