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简便运算(1)19.98x1997.1997-19.98x1996.1996-19.98x0.0001(2)1998x75-999x37-99.9x1110(3)(4.8x7.5x8.1)÷(2.4x2.5x2.7)(4)2006÷1.5+1008÷1.5+586÷1.5(5)199.7x199.7-19.95x1999

题目详情
简便运算
(1)19.98x1997.1997-19.98x1996.1996-19.98x0.0001
(2)1998x75-999x37-99.9x1110
(3)(4.8x7.5x8.1)÷(2.4x2.5x2.7)
(4)2006÷1.5+1008÷1.5+586÷1.5
(5)199.7x199.7-19.95x1999
▼优质解答
答案和解析
(1)19.98x1997.1997-19.98x1996.1996-19.98x0.0001
=19.98×(1997.1997-1996.1996-0.0001)
=19.98×(1997.1997-1996.1997)
=19.98×1
=19.98
(2)1998x75-999x37-99.9x1110
=999×2×75-999×(37+111)
=999×(150-148)
=999×2
=1998
(3)(4.8x7.5x8.1)÷(2.4x2.5x2.7)
=4.8/2.4×7.5/2.5×8.1/2.7
=2×3×3
=18
(4)2006÷1.5+1008÷1.5+586÷1.5
=(2006+1008+586)/(3/2)
=5088×2/3
=3392
(5)199.7x199.7-19.95x1999
=199.7²-(199.7-0.2)×(199.7+0.2)
=199.7²-1997.2²+0.2²
=0.04