Real Numbers

Mathematics — Second Preparatory

Common mistakes

Thinking the square root of a non-perfect square is rational, for example writing √10 = 3.
Believing a repeating decimal is irrational because its digits repeat. In fact, it is rational.
Confusing an irrational number with a negative number. The number −5 is rational because it equals −5/1.
Treating an approximation such as √2 = 1.41 as an exact value. It is only an approximation.

Real Numbers · 6 / 7