a) 17.( 15 -16) + 16. (17 -20)
= 17.(-1) + 16(-3)
= -17 -48
= -65
b) 23. ( 145 – 17) – 145.( 23 -6)
= 23.145 -23.17 -145.23 +145.6
= 23.(145-145) -23.17 +145.6
= 23.0 - 391 +870
= 479
c) -38.( 25 - 4) + 25.(- 4 + 38)
= -38.25 +38.4 -25.4 +25.38
= 25.(-38+38) +4.(38 -25)
= 25.0 +4.13
= 0 + 52
= 52
d) 24.(15 - 4) +4.(24 – 15)
= 24.15 -24.4 +24.4 -4.15
= 15.(24-4) -4.(24-24)
= 15.20 -4.0
= 300
e) -39.(5 – 99) +99.(10 – 39)
= -39.5 +39.99 +99.10 -99.39
= 39.(99-99) -39.5 +99.10
= 39.0 - 195 +990
= 795