Question

Tính nhanh:   a) 101²             b) 75²-50.75+25²            c) 103.97

Answer 1

\(a,101^2=101.\left(100+1\right)=10100+101=10201.\\ b,75^2-50.75+25^2\\ =75.\left(75-50\right)+25^2\\ =75.25+25^2\\ =25.\left(75+25\right)\\ =25.100\\ =2500.\)

Answer 2

\(c,103.97\\ =\left(100+3\right).97\\ =9700+291\\ =9991\)

Answer 3

a) \(101^2=101.101=10201\)

b) \(75^2-50.75+25^2\)

\(=75^2-2.25.75+25^2\)

\(=\left(75-25\right)^2=50^2=2500\)

c) \(103.97=\left(100+3\right).\left(100-3\right)\)

\(=100^2-3^2=9991\)