Question

Tính nhanh : 

a) 101² ; b) 199² ; c) 47.53

 

Answer 1

a) 101² = (100+1)^2 = 100^2 + 200 + 1 = 10 000 + 200 +1 = 10 201

 b) 199² = (200 -1)^2 = 200^2 - 400 +1 = 40 000 - 400 +1 = 39 601 

; c) 47.53 = (50-3) (50+3) = 50^2 - 3^2= 2500 -9 =2491

Answer 2

a) \(\left(100+1\right)^2=100^2+2\times100\times1+1^2=10000+200+1=10201\)

b)\(=\left(200-1\right)^2=200^2-2\times200\times1+1^2=40000-200+1=39801\)

c)\(=\left(50-3\right)\times\left(50+3\right)=50^2-3^2=2491\)

Answer 3

\(101^2=\left(100+1\right)^2=100^2+2.100.1+1^2=10000+200+1=10201\)

\(199^2=\left(200-1\right)^2=200^2-2.200.1+1^2=40000-400+1=39601\)

\(47.53=\left(50-3\right).\left(50+3\right)=50^2-3^2=2500-9=2491\)