Find a percent of a number
percent-of · applied · prompt: What is {p}% of {n}?
This is missing-value in context, with {"a": "p", "b": 100, "d": "n"}. p% of n means p/100 = x/n.
| Method | Idea | Best when | Calls |
|---|---|---|---|
Convert to a decimal and multiply decimal (= missing-value · unit_rate) |
{p}% = {p} ÷ 100; multiply that by {n}. | {a}/{b} is a friendly decimal. | to-decimal |
Find 1% first one_percent (= missing-value · scale_factor) |
1% of {n} is {n} ÷ 100; multiply by {p}. | {d} is a whole-number multiple of {b}. | — |
Multiply, then divide by 100 multiply_first (= missing-value · cross_multiply) |
{p} × {n} ÷ 100. | Always works; most useful when there’s no whole-number scale factor. | — |
Use a simplified fraction fraction (= missing-value · simplify_then_scale) |
Simplify {p}/100 to lowest terms, then take that fraction of {n}. | {a}/{b} isn’t in lowest terms. | simplify-fraction |
Ratio table ratio_table (= missing-value · ratio_table) |
Scale {p}:100 until the 100 becomes {n}. | {d} is a small whole-number multiple of {b}. | — |
Build from 10% and 5% benchmark_10_5 |
10% is easy (÷ 10) and 5% is half of that; add up the pieces. | The percent is a multiple of 5. | — |
Each graph starts at the question and branches at × Which first step? into every first step a student might write. Methods that share a first step meet there and split at × Which next step?. Each route then follows its method to the answer. The legend at the bottom of each graph explains the shapes.
What is 15% of 80?
Not applicable here: Ratio table (ratio_table)
What is 35% of 60?
Not applicable here: Ratio table (ratio_table)