Cross Multiplication Calculator
What if I wanna edit my calculations?
@Reader
The CrissXCross Formula
It’s pretty simple.
- Start with an equation of two fractions: a/b = c/d
- Multiply the numerator of the first fraction (a) by the denominator of the second fraction (d)
- Multiply the denominator of the first fraction (b) by the numerator of the second fraction (c)
- Set these products equal to each other: ad = bc
Why Would any one Want to Use This?
Compare fractions, solve equations involving fractions, find unknown values in proportions, and simplify algebraic equations with rational expressions.
Example: To solve x/8 = 2/x:
- Cross multiply: x × x = 8 × 2
- Simplify: x² = 16
- Solve: x = ±4
How to Use the Calculator
When you enter numerical values into any three of the four fields (A, B, C, and D), the calculator automatically computes the missing field. All calculated results are rounded to two decimal places.
The automatically calculated field is highlighted blue so you can easily tell which value was computed. If you change one of the three manually entered fields, the highlighted computed field will update immediately.
If you edit the highlighted field itself, the calculator assumes you want to recalculate its paired field. The pairings are:
- A ↔ B: Editing A recalculates B, and vice versa.
- C ↔ D: Editing C recalculates D, and vice versa. After you edit the computed field, the highlight shifts to the newly computed field.
If you clear any field (i.e., remove its value), no calculation occurs until three fields are filled again. Or you can click the Clear button to erase all values and remove any computed highlights.