参考答案

解①1÷(1+34)
=1÷74
=47；
②515+223-415
=71315-415
=735；
③2.8×5.6+3.4×245-280%
=2.8×（5.6+3.4-1）
=2.8×8
=22.4；
④213×12.5×67×8
=（73×67）×（12.5×8）
=2×100
=200；
⑤[1-0.8÷(23+215)]
=1-0.8÷0.8
=1-1
=0；
⑥7788×77
=5398；
⑦1÷[0.5×(214+0.25)-14]
=1÷[0.5×2.5-0.25]
=1÷[1.25-0.25]
=1÷1
=1；
⑧[4-(156-0.75)÷289]×227×227
=[4-1312×926]×227
=[4-38]×227
=298×227
=587；
⑨(67-79)×63
=67×63-79×63
=54-49
=5；
⑩(459×112+3149÷12)+[8916-(3916+445)]
=（459+3149）×112+[8916-3916-4.8]
=36×112+[5-4.8]
=3+0.2
=3.2．