Question

Tính nhanh:

a) 101^2

B)97*103

C) 77²+23²+77*46

D) 105²-5²

Answer 1

a) 101²

= (100 + 1)²

= 100² + 2.100 + 1

= 10000 + 200 + 1

= 10201

b) 97.103

= (100 - 3)(100 + 3)

= 100² - 3²

= 10000 - 9

= 9991

c) 77² + 23² + 77.46

= 77² + 2.77.23 + 23²

= (77 + 23)²

= 100²

= 10000

d) 105² - 5²

= (105 - 5)(105 + 5)

= 100.110

= 11000