9.5×2.1−9.5÷2.1+10.5×2.1−10.5÷2.1
问题描述:
9.5×2.1−9.5÷2.1+10.5×2.1−10.5÷2.1
答
9.5×2.1−9.5÷2.1+10.5×2.1−10.5÷2.1
=9.5×2.1+10.5×2.1−9.5÷2.1−10.5÷2.1
=(9.5×2.1+10.5×2.1)−(9.5÷2.1+10.5÷2.1)
=(9.5+10.5)×2.1-(9.5+10.5)÷2.1
=20×2.1-20÷2.1
=42-(210-10)/21
=42-10+10/21
=32又10/21