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# equation

noun (equation, equations)

«equation» in the English dictionary: everyday — its meanings, how the lessons use it, and examples, each with its tree on Mova.

## Everyday

1. An equation is a number sentence with an equals sign, showing that two sides have the same value, like 3 + 4 = 7. [tree →](https://mova.elamur.ai/free/en/corpora/dictionaries/school/E/equation/#m1)
2. An equation often has a missing number or letter to find, like x + 2 = 5. [tree →](https://mova.elamur.ai/free/en/corpora/dictionaries/school/E/equation/#m2)
3. In science, an equation is a short way to write a rule or a reaction. [tree →](https://mova.elamur.ai/free/en/corpora/dictionaries/school/E/equation/#m3)

### In the lessons

a number sentence that shows the problem, often with a missing number to find; in maths: solving an equation means finding the missing number that makes both sides equal; in science: equations show how things are related; phrases: «solve the equation», «write an equation», «balance the equation»

### Examples

- Write an equation for the story. [tree →](https://mova.elamur.ai/free/en/corpora/dictionaries/school/E/equation/#x1)
- Solve the equation 5 + □ = 12. [tree →](https://mova.elamur.ai/free/en/corpora/dictionaries/school/E/equation/#x2)
- The equation x − 4 = 9 means a number take away 4 is 9. [tree →](https://mova.elamur.ai/free/en/corpora/dictionaries/school/E/equation/#x3)
- Which equation matches the problem? [tree →](https://mova.elamur.ai/free/en/corpora/dictionaries/school/E/equation/#x4)
- An equation is like a balance: both sides weigh the same. [tree →](https://mova.elamur.ai/free/en/corpora/dictionaries/school/E/equation/#x5)
- Check your answer by putting it back into the equation. [tree →](https://mova.elamur.ai/free/en/corpora/dictionaries/school/E/equation/#x6)
- 2 + 3 = 5 is an equation, but 2 + 3 is not. [tree →](https://mova.elamur.ai/free/en/corpora/dictionaries/school/E/equation/#x7)
- Einstein's famous equation is E = mc². [tree →](https://mova.elamur.ai/free/en/corpora/dictionaries/school/E/equation/#x8)

### Note

Asks to write the operation as a number sentence or to find a missing number; the missing number is found with the opposite operation. Trap: in □ − 4 = 9 add 4 to 9, do not take 4 away. An equation must have an equals sign; whatever you do to one side, do to the other.

## On Mova

- [Trees and pragmatics of «equation» in the school dictionary](https://mova.elamur.ai/free/en/corpora/dictionaries/school/E/equation/): every meaning and example parsed by Mova, with its dependency tree and frames.
- [«equation» in the school dictionary](https://mova.elamur.ai/free/en/dictionaries/school/w/equation.html) on Mova free.