简便计算 2.48+2.46+2.51+2.43+2.49+2.53+2.55+2.51+2.47+2.50

2.5*10-0.02-0.04+0.01-0.07-0.01+0.03+0.05+0.01-0.03
=25-0.07
=24.93

=2.50*10-0.02-0.04-+0.01-0.07-0.01+0.03+0.05+0.01-0.03
=25-0.02-0.04-0.07+0.05(+0.01-0.01和+0.03-0.03抵掉了)
=25-0.02-0.04-0.02(-0.07+0.05能抵掉的就抵掉)
=25-0.08
=24.92

2.48+2.46+2.51+2.43+2.49+2.53+2.55+2.51+2.47+2.50=2.5*10+(-0.02-0.04+0.01-0.07-0.01+0.03+0.05+0.01-0.03+0)=25-0.08=24.92

2.50*10-0.02-0.04+0.01-0.07-0.01+0.03+0.05+0.01-0.03=25+0.03=25.03

2.5*10-0.02-0.04+0.01-0.07-0.01+0.03+0.05+0.01-0.03
=25-0.17+0.1
=24.93

取2.51为中心数。其余各数在其基础上加减。
即：2.51*10（共10个数）-0.03-0.05-0.08-0.02+0.02+0.04-0.04-0.01=25.1-0.17=24.93