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问几道简便运算①39*69+62*69-69②15*25+25*25③56*386-286*56-56*98④61*13+39*13⑤38*547-347*38-150*38⑥63*73-63*63

题目详情
问几道简便运算
①39*69+62*69-69 ②15*25+25*25 ③56*386-286*56-56*98
④61*13+39*13 ⑤38*547-347*38-150*38 ⑥63*73-63*63
▼优质解答
答案和解析
①39*69+62*69-69
=69*(39+62-1)
=69*100
=6900
②15*25+25*25
=25*(15+25)
=25*40
=1000
③56*386-286*56-56*98
=56(386-286-98)
=56*2
=112
④61*13+39*13
=13*(61+39)
=13*100
=1300
⑤38*547-347*38-150*38
=38*(547-347-150)
=38*50
=1900
⑥63*73-63*63
=63*(73-63)
=63*10
=630