Add two fractions
add-fractions · core · prompt: Find {a}/{b} + {c}/{d}.
Its methods call: common-multiple, cross-products, missing-value, simplify-fraction, to-decimal
| Method | Idea | Best when | Calls |
|---|---|---|---|
Common denominator common_denominator |
Rewrite both fractions over a common denominator, add the numerators, simplify. | Always; use the least common multiple to keep numbers small. | common-multiple, missing-value, simplify-fraction |
Bow-tie (cross-multiply) bow_tie |
({a}×{d} + {c}×{b}) / ({b}×{d}), then simplify. | Quick, with small denominators. | cross-products, simplify-fraction |
Convert to decimals decimal |
Write each fraction as a decimal and add. | An approximate answer is enough. | to-decimal |
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.
Find 5/6 + 3/4.
Find 2/3 + 1/5.
