4.2 Small Group · Group 2
Second Challenge Form · Non-Routine Extension · Same Standard, New Problems
Visual Models · Fractions, Decimals, and Percents · Percent · Procedural Fluency
- You already can do this. So we go up a level, not up a number: find what is always true, show it a second way, and be ready to defend it with a reason instead of an answer.
- A player scored 3/4 of the points. Percent means out of 100, so I want an equivalent fraction with 100 on the bottom.
- What do I multiply the denominator 4 by to get 100? 4 × 25 = 100, so my scale factor is 25.
- I have to multiply the top by that same 25: 3 × 25 = 75. So 3/4 = 75/100.
- 75 out of 100 is 75%. And 75/100 as a decimal is 0.75, because hundredths sit two places after the point.
- So 3/4 = 75/100 = 0.75 = 75%. All three name the same score.
- Let's change 1/5 into a fraction out of 100, then a decimal and a percent.
- What do we multiply the denominator 5 by to get 100? (20)
- Now multiply the numerator by that same 20: 1 × 20 = ? (20) So 1/5 = 20/100.
- 20 out of 100 is what percent? (20%) And as a decimal? (0.2)
- Now prove it: say why that move had to work at all — not just that it did.
- Sentence frame — convince a skeptic: "My method works because ___ . It would stop working if ___ ."
- Fractions, Decimals, and Percents (Fracciones, decimales y porcentajes) — Three equivalent ways to name the same part of a whole.
- Percent (Porcentaje) — A way to compare a number to 100, shown with the % sign.
- Decimal (Decimal) — A number with a dot, like 0.5, that shows a part less than one.
- Equivalent (Equivalente) — Having the same value, just written a different way.
- Benchmark (Referencia) — A familiar number you use to guess, like 50% or 1/2.
- Discount (Descuento) — Money taken off the first price to make it cheaper.
- A common mistake in Relate Fractions, Decimals, and Percents is treating the numerator and denominator as the percent's digits — turning 3/5 into "35%" by just reading the 3 and the 5. Percent means out of 100, so the fix is to build an equivalent fraction with denominator 100: 5 × 20 = 100, so multiply the top by 20 too — 3/5 = 60/100 = 60%. A second version of this mistake is scaling only ONE part of the fraction (writing 3/5 = 3/100 or 60/5). Whatever you multiply the denominator by, you must multiply the numerator by the same number. When a denominator will not reach 100 evenly (8, 3, 7), divide the numerator by the denominator instead and then multiply by 100.
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1 MULTIPLE CHOICE
Convert 7/20 to a percent.
- A35%
- B70%
- C20%
- D14%
Rewrite each fractionWork it outSimplify -
2 MULTIPLE CHOICE
Which decimal is equivalent to 45%?
- A0.45
- B4.5
- C0.045
- D45.0
Work -
3 MULTIPLE CHOICE
A game shows your score as 7/8 complete. What percent is that?
- A87.5%
- B78%
- C75%
- D88%
Rewrite each fractionWork it outSimplify
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4 ERROR ANALYSIS
Fix our table's thinking
- 1The problem:A game shows your score as 7/8 complete. What percent is that?
- 2A classmate at our table answered:88%
Which step contains the error? Explain the mathematical misconception and write the correct calculation below.
✏️ Corrected Mathematical Work & Explanation -
5 ERROR ANALYSIS
Spot the Common Mistake
- 1Convert 5/8 to a percent:5/8
- 2Divide the bottom by the top:8 ÷ 5 = 1.6
- 3Multiply by 100:1.6 × 100 = 160%
- 4Final answer:5/8 = 160%
Which step contains the error? Explain the mathematical misconception and write the correct calculation below.
✏️ Corrected Mathematical Work & Explanation -
6 ERROR ANALYSIS
Find the Conversion Error
- 1Convert 2/3 to a percent:2/3
- 2Divide numerator by denominator:2 ÷ 3 = 0.67
- 3Move decimal two places:0.67 → 67%
- 4Final answer:2/3 = 67%
Which step contains the error? Explain the mathematical misconception and write the correct calculation below.
✏️ Corrected Mathematical Work & Explanation
Writing Task: Justify why your mathematical solution is accurate and complete.