Numbers allows us to express and compare magnitudes and quantities.
A number can be written in many different ways. For example, all of these
expressions and numerals represent the same number:
$$
4 \qquad
1\times 4 \qquad
4.00 \qquad
\text{four} \qquad
3+1 \qquad
\frac{28}{7} \qquad
\sqrt{16} \qquad
\sqrt[\footnotesize 3]{64} \qquad
(-4)Γ(-1) \qquad
3.99β¦ \\qquad
2^2 \newline
\text{\huge β} \qquad
\texttt{0b100} \qquad
\text{11}_3 \qquad
\text{β
£} \qquad
\text{π£} \qquad
\text{π} \qquad
\text{β } \qquad
\text{ΞΚΉ} \qquad
\text{ε} \qquad
\text{λ·} \qquad
\text{Ω€} \qquad
\text{Χ} \qquad
\text{α€} \qquad
\text{π} \qquad
\text{ΰ§ͺ} \qquad
$$