Simplify ab2c3×a4b5c−6a−7b−8c9×a10b11c−12×a13b−14c15
Simplify:
(1) 2+(−4)−(+3)
(2) −5+4−(−2)
(3) 10+(−5)−(−4)
(4) 12−(+6)+(−3)
(5) −15+(−4)−(+3)