计算: ( 1 3 ) - 1 - 2 cos 45 ° + | 1 - 2 | - ( 3 + 1 ) 0 .
计算①–2-5+23-9+7 ② ③ ④
(本题6分)计算:
计算: (1) (2)
计算:(每题4分,共8分)(1)(2)
(8分)计算:(1)(2)(3); (4)