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1.1+1.2+1.3+1.4+1.5+1.6+1.7+1.8+1.8+1.9+2+2.1+2.2+2.3+2.4+2.5+2.6+2.7+2.8+2.9一直加到4.9,求怎样巧算

题目详情
1.1+1.2+1.3+1.4+1.5+1.6+1.7+1.8+1.8+1.9+2+2.1+2.2+2.3+2.4+2.5+2.6+2.7+2.8+2.9
一直加到4.9,求怎样巧算
▼优质解答
答案和解析
1.1+5=6.1
1.2+4.9=6.1
1.3+4.8=6.1
.
共有20个6.1
6.1*20=122