(1)23-17-(-7)+(-16)
=23-17+7-16
=23-10-16
=13-16
=-3
(2)123×80%=x×(1+10%)
123×0.8=1.1x
123×8=11x
11x=984
x=984/11
(3)1-(1-0.5)÷3×[2-(-3)的2次方]
=1-0.5÷3×[2-9]
=1-1/2÷3×(-7)
=1+1/2÷3×7
=1+1/2×1/3×7
=1+7/6
=13/6