Question

Using the brackets solve $106\times 99$.

Answer 1

Simplification:

We have $106\times 99$

We can also write the above expression as

$$\begin{gathered} 106\times 99=(100+6)\times (100-1) \\ =100\times 100-100\times 1+6\times 100-6\times 1\left\{\text{Since}\left(a+b\right)\text{×}\left(c-d\right)\text{=a×c-a×d+b×c-b×d}\right\} \\ =10000-100+600-6 \\ =10000+600-100-6 \\ =10600-106 \\ =10494 \end{gathered}$$

Hence $106\times 99=10494$