98-96+94-92+90-88+.+18-16+14-12
=(98-96)+(94-92)+(90-88)+.+(18-16)+(14-12)
=2+2+2+...+2+2
=2*[(98-12)/2+1]/2
=[(98-12)/2+1]
=43+1
=44
关键是搞清楚最后是几个2相加.
98-96+94-92+90-88+.+18-16+14-12
=(98-96)+(94-92)+(90-88)+.+(18-16)+(14-12)
=2+2+2+...+2+2
=2*[(98-12)/2+1]/2
=[(98-12)/2+1]
=43+1
=44
关键是搞清楚最后是几个2相加.