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脱式计算.(怎样简便就怎样计算.)69×102-2×69125×87×815.64-2.53-7.47101×466.7+2.63+4.361000÷(61×5)5824÷8×(85-78)840÷28+70×18.

题目详情
脱式计算.(怎样简便就怎样计算.)
69×102-2×69         
125×87×8      
15.64-2.53-7.47
101×46       
 6.7+2.63+4.3        
61000÷(61×5)
5824÷8×(85-78)
840÷28+70×18.
▼优质解答
答案和解析
(1)69×102-2×69
=69×(102-20)
=69×100
=6900;

(2)125×87×8
=125×8×87
=1000×87
=87000;

(3)15.64-2.53-7.47
=15.64-(2.53+7.47)
=15.64-10
=5.64;

(4)101×46 
=(100+1)×46
=100×46+1×46
=4646;

(5)6.7+2.63+4.3   
=6.7+4.3+2.63
=11+2.63
=13.63;

(6)61000÷(61×5)
=61000÷61÷5
=1000÷5
=200;

(7)5824÷8×(85-78)
=728×7
=5096;

(8)840÷28+70×18
=30+1260
=1290.