计算:(1)18−6÷(−2)×(−13);
1个回答

(1)18−6÷(−2)×(−

1

3)

=18-(-3)×(-[1/3])

=18-(3×[1/3])

=18-1

=17;

(2)(−3)2×[−

2

3+(−

5

9)]

=9×[-[2/3]+(-[5/9])]

=9×(-[2/3])+9×(-[5/9])

=(-6)+(-5)

=-(6+5)

=-11;

(3)(

1

4−

1

2−

1

8)×16

=[1/4]×16-[1/2]×16-[1/8]×16

=4-8-2

=4+(-8)+(-2)

=4+[(-8)+(-2)]

=4+(-10)

=-(10-4)

=-6;

(4)−14−

1

7×[2−(−3)2]

=-1-[1/7]×(2-9)

=-1-[1/7]×[2+(-9)]

=-1-[1/7]×(-7)

=-1-(-1)

=-1+1

=0.