Question

1、求:123+234+345+456+567+678+789—————————————————— 12.3+23.4+

Answer 1

123+234+345+456+567+678+789

—————————————————— 12.3+23.4+34.5+45.6+56.7+67.8+78.9

=7乘10除以7

=10

39×148149 +148×86149 +48×74149=

互相抵消,的148

1+2+3+4+5+6+7+8+7+6+5+4+3+2+1=

（1+8）乘8除2=36 (7+1)乘7除以2=28

28+36=64

64和888888化简再乘888888