To express the fraction $\frac{2}{5}$ as a percentage, we find that it is equal to $40\%$.

To convert a fraction into a percentage, you multiply the fraction by $100$. The term “percent” translates to “per hundred,” so this process reveals how many parts of a hundred the fraction represents. For the fraction $\frac{2}{5}$, we follow these steps:

1. Multiply the numerator (2) by $100$: $2 \times 100 = 200$
2. Divide the result by the denominator (5): $200 \div 5 = 40$

Thus, we conclude that $\frac{2}{5}$ is equivalent to $40\%$. This conversion method can be applied to any fraction: simply multiply by $100$ and then divide by the denominator. Grasping this technique is essential for converting fractions to percentages, a skill frequently required in many GCSE Maths problems.