Evaluate:
^@ 29 \times 31 ^@
Answer:
^@ 899 ^@
- We know that
^@ a^2 - b^2 = (a - b) (a + b) ^@ - Thus, @^ \begin{aligned} 29 \times 31 & = (30 - 1) \times (30 + 1) && [\text{Using}, a^2 - b^2 = (a - b) (a + b)] \\ & = [(30)^2 - 1^2] \\ & = (900 - 1) \\ & = 899 \end{aligned} @^