(-49)-(+91)-(-5)+(-9) -4.2+5.7-8.4+10
问题描述:
(-49)-(+91)-(-5)+(-9) -4.2+5.7-8.4+10
前后两题的.
答
原式=-49-91+5-9-4.2+5.7-8.4+10
=(5+5.7+10)-(49+91+9+4.2+8.4)
=20.7-161.6=140.9