Question

Tính nhanh: \({49^2}\)

Answer 1

Ta có: \({49^2} = {\left( {50 - 1} \right)^2} = {50^2} - 2.50.1 + {1^2} = 2500 - 100 - 1 = 2401\)

Vậy: \({49^2} = 2401\)