A number decreased by 23% becomes 539. Find the number.

Let the number be $x$.

The number decreased by 23%.

Hence,

⇒ $x - 23$% of $x = 539$

⇒ $x - \dfrac{23}{100} \times x = 539$

⇒ $\dfrac{100}{100} \times x - \dfrac{23}{100} \times x = 539$

⇒ $\dfrac{(100 - 23)}{100} \times x = 539$

⇒ $\dfrac{77}{100} \times x = 539$

⇒ $x = \dfrac{539 \times 100}{77}$

⇒ $x = \dfrac{53,900}{77}$

⇒ $x = 700$

Hence, the number is 700.