7.8*1.25+8等于几?(要巧算)

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7.8*1.25+8等于几?(要巧算)

原式=(8-0.2)*1.25+8
=8*1.25-1/5*1.25+8
=10-0.25+8
=9.75+8
=17.75

7.8*1.25+8
=7.8×5/4+8
=39/4+8
=9.75+8
=17.75