Question

Find the prime factorisation of $980$.

Answer 1

Solve by prime factorisation:

Given number is $980$

$$\begin{gathered} \begin{array}{cc}2& 980\\ 2& 490\\ 5& 245\\ 7& 49\\ 7& 7\\ & 1\end{array} \\ \Rightarrow 980=2\times 2\times 5\times 7\times 7 \end{gathered}$$

Therefore, the prime factorisation of $980$ is $2\times 2\times 5\times 7\times 7$.