Lesson 3.13.1 Small Group · Group 1
Start hereWords, worked example, and sentence starters
Learning target With my small group, I can write and describe a ratio that compares two quantities — one step at a time, with support.
Start hereWords for this lesson
Read each word before you begin. Say it out loud.
| Word | What it means | Example |
|---|---|---|
| RatioSpanish: Razón | A way to compare two amounts, like 3 to 2. | 3 to 5 ■■■ □□□□□ |
| ComparisonSpanish: Comparación | Looking at two or more amounts to see how they are related. | 5 eggs vs. 3 eggs — which recipe uses more? |
| Part-to-partSpanish: Parte a parte | A ratio comparing one part of a group to another part. | apples to oranges |
| Part-to-wholeSpanish: Parte a todo | A ratio comparing one part to the whole group. | apples to all the fruit |
| Colon notationSpanish: Notación con dos puntos | Writing a ratio with two dots between the numbers, like 3:2. | 3 to 2 can be written as 3:2 |
| Tape diagramSpanish: Diagrama de cintas | A bar cut into equal parts that shows how two amounts in a ratio compare, and how they make up the whole. | 3 equal parts of apple juice beside 2 equal parts of sparkling water — 5 parts of fruit drink in all. |
How it worksWorked example
These numbers are not on your problems. The steps are. Follow them with your own numbers.
- Count each group. pens = 10 pencils = 4
- Write them in the order the question asks — pens FIRST.
- Write all three forms: 10 to 4 · 10 : 4 · 10/4
- Simplify: divide both terms by 2. 10 : 4 → 5 : 2
Answer: The ratio of pens to pencils is 5 : 2 in simplest form.
Now you trySame steps, your turn
The steps are the same as the worked example. The numbers are yours. Do the work.
A bowl has 4 apples and 1 orange. Write the ratio of apples to oranges. Then write the ratio of apples to all the fruit.
Say it and write itSentence starters
Finish each sentence out loud with a partner. Then use them in your writing.
- The ratio of to is .
- This means for every , there are .
- The order matters because .
- I simplified by dividing both terms by .
Word bank ratiotermcomparefor everypartwholetotalsimplest formdivideorderfirstsecond
Watch outA common mistake
A common mistake in Understand Ratios is writing the ratio in the wrong order: when asked for the ratio of apple juice to sparkling water in a recipe that uses 3 cups of apple juice for every 2 cups of sparkling water, some students write 2:3 (sparkling water to apple juice) because they list the ingredients in whatever order comes to mind rather than the order the question asks for. The two ratios describe different drinks — 3:2 means 3 cups of juice for every 2 cups of water, while 2:3 would mean only 2 cups of juice for every 3 cups of water. Always match the order of your ratio to the order named in the question: "apple juice to sparkling water" means the apple juice number comes first, giving 3:2.
Lesson 3.13.1 Small Group · Group 1
Group 1Supported practice
Learning target With my small group, I can write and describe a ratio that compares two quantities — one step at a time, with support.
-
1Complete each step, then write the final answer.
The counts from the problem, in order. A fruit cup has 5 grapes for every 2 strawberries. Write the ratio of grapes to strawberries.
- 1Which fruit do the words name first?
- 2Read the table. Grapes to strawberries is 5 to ?. What is the missing number?
- 3Write the ratio with a colon.
Final answer: -
2Complete each step, then write the final answer.
The Total row is all the players. A team has 6 girls and 5 boys. Write the ratio of boys to all the players.
- 1Add to fill the Total row. How many players are there?
- 2Which number goes first: the boys or all the players?
- 3Write boys to all the players with a colon.
Final answer: -
3Complete each step, then write the final answer.
A bag has 3 red marbles and 8 green marbles. The ratio of green marbles to red marbles is ? : 3. What is the missing number?
Show your workHint Green comes first in this ratio. How many green marbles are there?
Final answer: -
4Complete each step, then write the final answer.
Chef Reyes mixes 4 cups of apple juice with 3 cups of sparkling water. The ratio of apple juice to the whole drink is 4 to ?. What is the missing number?
Show your workHint The whole drink is the juice and the water together.
Final answer: -
5Complete each step, then write the final answer.
A box has 12 crayons. 5 are red and the rest are blue. The ratio of blue crayons to red crayons is ? : 5. What is the missing number?
Show your workHint First find how many crayons are blue. 12 is all the crayons.
Final answer: -
6Circle the letter of the best answer. Show how you know.
Lily has 3 cats and 4 dogs. Ben says the ratio of dogs to cats is 3:4. Which ratio of dogs to cats is correct?
- A4:3
- B3:4
- C4:7
- D3:7
Hint Which animal do the words name first? Its number goes first.
Show your work
Explain your thinkingBen wrote 3:4 for dogs to cats. Why does the order of the numbers matter in a ratio?
Sentence starter Dogs to cats is ___ because the words say ___ first. · If I switch the order, the ratio compares ___ to ___.