Question

49X49十49X（40十6）X25简便方法计算？

Answer 1

49×(40+6+3)+49×(40+6)×25

=49×(40+6)+49×3+49×(40+6)×25

=49×(40+6)×26+49×3

=49×(46×26+3)

=49×(26+20)×26+49×3

=26×49×26+49×20×26+49×3

Answer 2

49x49十49x(40十6)x25
=49x(50-1)+49x50x25
=49x50-49x1+49x50x25
=49x50+49x50x25-49
=49x50x(1+25)-49
=49x(50x26-1)
=49x129
=6321。