# Mathematical English: Powers

Non-native speakers often struggle when they have to speak about powers. For example, the correct expression used for $10^3$ is “ten to the power of three“, although it is common to instead use the shorter form “ten to the three“. Similarly, $x^7$ is “x to the (power of) seven“. The exponents 2 and 3 (can you think of other examples?) have special names: $x^2$ is “x squared“, $x^3$ is “x cubed“. A confusing yet common mistake is to say “ten to three” (which refers to the time of day 2:50) instead of “ten to the three“. If the exponent is negative, for example $10^{-3}$, the correct expression is “10 to the (power of) minus three“, but not “10 to the (power of) negative three“. Finally, the correct form for $e^x$ is either “exponential function of x” or, much shorter, “e to the (power of) x“.