(i) −27 − (−23)
= −27 + 23
= −4
(ii) −17 −18 − (−35)
= −17 − 18 + 35
= −35 + 35
= 0
(iii) −12 − (−5) − (−125) + 270
= −12 + (5 + 125 + 270)
= −12 + 400
= 388
(iv) 373 + (−245) + (−373) + 145 + 3000
= 373 − 245 − 373 + (145 + 3000)
= 128 − 373 + 3145
= −245 + 3145
= 2900
(v) 1 + (−475) + (−475) + (−475) + (−475) + 1900
= 1 (−475 − 475 − 475 − 475 ) + 1900
= 1 − 1900 + 1900
= 1
(vi) (−1) + (−304) + 304 + 304 + (−304) + 1
= −1 + (−304 + 304) + ( 304 − 304) + 1
= −1 + 0 + 0 + 1
= 0