Question

脱式计算题简便运算

Answer 1

34×3.535-3.5×34.34
=34×3.5×1.01-3.5×34×1.01
=0
8+89+899+8999+89999
=9+90+900+9000+90000-5
=99999-5
=99994
0.67×2.1+0.018×21+8.5×0.79
=0.67×2.1+0.18×2.1+8.5×0.79
=(0.67+0.18)×2.1+8.5×0.79
=0.85×2.1+0.85×7.9
=0.85×(2.1+7.9)
=0.85×10
=8.5
22222.2×9.99999
=22222.2×(10-0.00001)
=222222-0.222222
=222221.777778
1997×19961996-1996×19971997
=1997×1996×10001-1996×1997×10001
=0
0.02+0.04+0.06+0.08+……+19.94+19.96+19.98
=(0.02+19.98)×999÷2
=10×999
=9990
99999×77778+33333×66666
=99999×77778+99999×22222
=99999×(77778+22222)
=99999×100000
=9999900000