计算:(1)2×(-5)+23-3÷.
计算: (1) (2)
计算:(每题4分,共8分)(1) (2)
(8分)计算:(1)(2)(3); (4)
计算.
计算:(第(1)题3分,其余各题每题4分,共19分)(1)-3-(-4)+7 (2)(3) (4)(5)