数学题求答案。。。 20
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请问是能简算的就要简算是吧?
①3又7/8-1/4+3/4+1/8
=3又7/8-(1/4+3/4)+1/8
=3又7/8-1+1/8
=2又7/8+1/8
=3
②5-1/6+5/6-1
=(5-1)-(1/6+5/6)
=4-1
3
③1/10+3/8-2/5
=(1/10-2/5)+3/8
=7/10+3/8
=43/40
④2.8*2.72+6.28*2.8
=2.8*(2.72+6.28)
=2.8*9
=25.2
⑤2/3+4/5-(3/5-1/15)
=2/3+(4/5-3/5)+1/15
=2/3+1/5+1/15
=14/15
①3又7/8-1/4+3/4+1/8
=3又7/8-(1/4+3/4)+1/8
=3又7/8-1+1/8
=2又7/8+1/8
=3
②5-1/6+5/6-1
=(5-1)-(1/6+5/6)
=4-1
3
③1/10+3/8-2/5
=(1/10-2/5)+3/8
=7/10+3/8
=43/40
④2.8*2.72+6.28*2.8
=2.8*(2.72+6.28)
=2.8*9
=25.2
⑤2/3+4/5-(3/5-1/15)
=2/3+(4/5-3/5)+1/15
=2/3+1/5+1/15
=14/15
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