4.5 · Part II
Supported Application · Guided Entry to Today's Problem
Determine the Whole Given the Part and Percent · Part
- Identify the given part and the percentage it represents
- Convert the percent to a decimal or fraction
- Divide the part by the percent decimal to find the total whole (100%)
- Determine the Whole Given the Part and Percent (Hallar el total dados la parte y el porcentaje) — Working backwards from a part and its percent to find the whole amount it came from.
- Part (Parte) — The amount you already know — the piece of the whole that the percent describes.
- Whole (Total) — The full amount the percent is measured against. The whole is always 100%.
- Double number line (Recta numérica doble) — Two lines lined up — dollars on one, percents on the other — so matching marks show the same amount two ways.
- Equation (Ecuación) — A math sentence with an equal sign. Here it says percent × whole = part, with the whole unknown.
- Percent (Porcentaje) — A ratio comparing a number to 100. To compute with it, write it in decimal form: 60% = 0.6.
- A common mistake when finding the whole is multiplying by the percent instead of dividing. For "$42 is 60% of the original price," computing 0.6 × 42 = $25.20 makes the original price SMALLER than the sale price — impossible for a discount. Since percent × whole = part, the whole is found by dividing: 42 ÷ 0.6 = $70. Whenever the percent is less than 100%, the whole must come out larger than the part, so a smaller answer is the tell.
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1 DRAG SORT
Sort each number by the role it plays in "$42 is 60% of the original price."
- $42
- 60%
- the original price
- the amount Akela paid
- 0.6
- 100%
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2 MULTIPLE CHOICE
75 minutes is 15% of the school day. How long is the school day?
- A500 minutes
- B11.25 minutes
- C90 minutes
- D1,125 minutes
Work- 1Whole100% is what number?
- 2Find 10%Divide by 10.
- 3BuildAdd or multiply to the percent.
- 4CheckIs it under or over the whole?
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3 MULTIPLE CHOICE
(Lesson 4.4) What is 20% of 150?
- A30
- B20
- C35
- D75
Work- 1Whole100% is what number?
- 2Find 10%Divide by 10.
- 3BuildAdd or multiply to the percent.
- 4CheckIs it under or over the whole?
Writing Task: Justify why your mathematical solution is accurate and complete.
4.5 · Part II
On-Level Application · Standard Rigor
Determine the Whole Given the Part and Percent · Part
- Identify the given part and the percentage it represents
- Convert the percent to a decimal or fraction
- Divide the part by the percent decimal to find the total whole (100%)
- Determine the Whole Given the Part and Percent (Hallar el total dados la parte y el porcentaje) — Working backwards from a part and its percent to find the whole amount it came from.
- Part (Parte) — The amount you already know — the piece of the whole that the percent describes.
- Whole (Total) — The full amount the percent is measured against. The whole is always 100%.
- Double number line (Recta numérica doble) — Two lines lined up — dollars on one, percents on the other — so matching marks show the same amount two ways.
- Equation (Ecuación) — A math sentence with an equal sign. Here it says percent × whole = part, with the whole unknown.
- Percent (Porcentaje) — A ratio comparing a number to 100. To compute with it, write it in decimal form: 60% = 0.6.
- A common mistake when finding the whole is multiplying by the percent instead of dividing. For "$42 is 60% of the original price," computing 0.6 × 42 = $25.20 makes the original price SMALLER than the sale price — impossible for a discount. Since percent × whole = part, the whole is found by dividing: 42 ÷ 0.6 = $70. Whenever the percent is less than 100%, the whole must come out larger than the part, so a smaller answer is the tell.
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1 MULTIPLE CHOICE
Which statement correctly names the pieces of "18 students is 30% of the class"?
- A18 is the part, 30% is the percent, the class size is the whole
- B18 is the whole, 30% is the part
- C30 is the part, 18 is the percent
- DThe class size is the part
✏️ Workspace & Solution Steps
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2 MULTIPLE CHOICE
A car is now worth $26,600, which is 70% of its purchase price. What was the purchase price?
- A$38,000
- B$18,620
- C$26,670
- D$45,200
Work -
3 MULTIPLE CHOICE
$10 is 50% of what number?
- A$20
- B$5
- C$60
- D$100
Work
Writing Task: Justify why your mathematical solution is accurate and complete.
4.5 · Part II
Extension & Non-Routine Application
Determine the Whole Given the Part and Percent · Part
- Identify the given part and the percentage it represents
- Convert the percent to a decimal or fraction
- Divide the part by the percent decimal to find the total whole (100%)
- Determine the Whole Given the Part and Percent (Hallar el total dados la parte y el porcentaje) — Working backwards from a part and its percent to find the whole amount it came from.
- Part (Parte) — The amount you already know — the piece of the whole that the percent describes.
- Whole (Total) — The full amount the percent is measured against. The whole is always 100%.
- Double number line (Recta numérica doble) — Two lines lined up — dollars on one, percents on the other — so matching marks show the same amount two ways.
- Equation (Ecuación) — A math sentence with an equal sign. Here it says percent × whole = part, with the whole unknown.
- Percent (Porcentaje) — A ratio comparing a number to 100. To compute with it, write it in decimal form: 60% = 0.6.
- A common mistake when finding the whole is multiplying by the percent instead of dividing. For "$42 is 60% of the original price," computing 0.6 × 42 = $25.20 makes the original price SMALLER than the sale price — impossible for a discount. Since percent × whole = part, the whole is found by dividing: 42 ÷ 0.6 = $70. Whenever the percent is less than 100%, the whole must come out larger than the part, so a smaller answer is the tell.
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1 MULTIPLE CHOICE
Marcus completed 18 math problems, which represents exactly 60% of his homework assignment. How many total problems are on the assignment?
- A30 problems
- B28 problems
- C24 problems
- D36 problems
Work -
2 MULTIPLE CHOICE
A shop reports that this week's $60 in sales is 120% of last week's. Was last week better or worse, and by how much?
- AWorse — last week was $50, so sales rose by $10
- BBetter — last week was $72, so sales fell
- CWorse — last week was $48
- DYou cannot tell without knowing the number of items sold
✏️ Workspace & Solution Steps
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3 OPEN RESPONSE
A toy store's puzzle stock was 25% 300-piece, 15% 500-piece, and the rest 1,000-piece. During a sale the store sold ALL of its 300-piece and 500-piece puzzles — 120 puzzles in total. How many of each type did the store have before the sale? Explain your reasoning.
✏️ Mathematical Justification & Response
Writing Task: Justify why your mathematical solution is accurate and complete.