Determine the Whole Given the Part and Percent
Name Period
Objectives / Objetivos
Content Objective: I can use equivalent ratio tables to determine the whole when I know a part and the percent it represents.
Language Objective: I can explain how an equivalent ratio table helps me scale a known part and percent to 100%.
Key Idea / Idea clave
Finding the whole with an equivalent ratio table. 1. Write the known percent and part in matching columns. 2. Apply the same scale factor to both columns until the percent reaches 100%; the matching amount is the whole. 3. Check by finding the given percent of that whole.
I Notice / Observo
- I notice the amount I know is only a ___ of the whole.
- I notice the whole would be marked ___%.
I Wonder / Me pregunto
- I wonder how I get from ___% back up to 100%.
Vocabulary / Vocabulario
| Term / Término | Definition / Definición |
|---|---|
| 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. Trabajar al revés a partir de una parte y su porcentaje para hallar el total del que proviene. |
| Part Parte | The amount you already know — the piece of the whole that the percent describes. La cantidad que ya conoces: el pedazo del total que describe el porcentaje. |
| Whole Total | The full amount the percent is measured against. The whole is always 100%. La cantidad completa contra la que se mide el porcentaje. El total siempre es 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. Dos rectas alineadas —dólares en una y porcentajes en la otra— para que las marcas correspondientes muestren la misma cantidad de dos formas. |
| Equation Ecuación | A math sentence with an equal sign. Here it says percent × whole = part, with the whole unknown. Una oración matemática con signo de igual. Aquí dice porcentaje × total = parte, con el total desconocido. |
| Percent Porcentaje | A ratio comparing a number to 100. To compute with it, write it in decimal form: 60% = 0.6. Una razón que compara un número con 100. Para calcular con él, escríbelo en forma decimal: 60 % = 0.6. |
Practice Preview / Vista previa de práctica
Read each task. Show your work in the spaces provided and explain how you know.
1. $20 is 50% of what number?
- A $10
- B $25
- C $40
- D $70
Answer:
2. Which statement correctly names the pieces of "18 students is 30% of the class"?
- A 18 is the whole, 30% is the part
- B 30 is the part, 18 is the percent
- C The class size is the part
- D 18 is the part, 30% is the percent, the class size is the whole
Answer:
3. A sweater's sale price of $42 is 60% of the original price. Each section is 10%. Use the bar model to find the original price.
4. Find the error
Which step has the mistake, and what should it be?
Reflection / Reflexión
One thing I learned today / Una cosa que aprendí hoy: