Estimate the Percent of a Number

6.AT.4 · Unit 4 · Lesson 3

Name   Period

Objectives / Objetivos

Content Objective: I can estimate the percent of a number using benchmark percents, rounding, and compatible numbers.

Language Objective: I can explain an estimate using the words about, benchmark, and compatible numbers.

Key Idea / Idea clave

Estimating Percents of Numbers. 1. Use benchmark percents: 10% (move decimal left 1), 1% (move left 2), 50% (half), 25% (quarter). 2. Combine benchmarks (e.g. 15% = 10% + 5%; 75% = 50% + 25%). 3. Round numbers to compatible values for quick mental estimates

Vocabulary / Vocabulario

Term / TérminoDefinition / Definición
estimate
estimación		A reasoned answer that is close enough to be useful, found without exact computation.
Una respuesta razonada, lo bastante cercana para ser útil, sin cálculo exacto.
benchmark percent
porcentaje de referencia		A friendly percent — 1%, 10%, 25%, 50%, 75%, 100% — used as a landmark for estimating.
Un porcentaje amigable — 1%, 10%, 25%, 50%, 75%, 100% — que sirve de punto de referencia.
compatible numbers
números compatibles		Numbers close to the originals that are easy to compute with mentally.
Números cercanos a los originales con los que es fácil calcular mentalmente.
double number line
recta numérica doble		Two parallel number lines that pair amounts with their percents at the same positions.
Dos rectas paralelas que emparejan cantidades con sus porcentajes en las mismas posiciones.
the whole
el todo		The quantity that counts as 100% in a problem — and it can change between questions.
La cantidad que representa el 100% en un problema, y puede cambiar entre preguntas.

Practice Preview / Vista previa de práctica

  1. Margaret's phone has 6 GB of storage and 4 GB is used. About what percent is used?
    1. About 70%
    2. About 40%
    3. About 25%
    4. About 150%
  2. The Green-Team recycled 216 pounds; 8.6% was metal. Using compatible numbers 10% and 200, the estimate is:
    1. 20 pounds
    2. 2 pounds
    3. 208 pounds
    4. 86 pounds
  3. Photos use 3.5 GB of the 4 GB of used storage. About what percent of the USED storage is photos?
    1. About 87%
    2. About 58%
    3. About 35%
    4. About 99%
  4. Two students estimate 8.6% of 216. Ana uses 10% of 220 = 22. Ben uses 10% of 200 = 20. Whose estimate is closer to the exact answer, 18.576?
    1. Ben's — 20 is 1.4 away; Ana's 22 is 3.4 away
    2. Ana's — 22 is closer to 18.576
    3. They are equally close
    4. Neither is a valid estimate

Reflection / Reflexión

One thing I learned today / Una cosa que aprendí hoy: