a, 17.85 + 15.17
= 17 . ( 85 +15 )
=17 .100
=1700
b, (-38) + 15+|38|+ (-15) + 120
= (-38 ) + 15 + 38 + (-15) +120
= [ (-38) +38 ) ] + [ 15 + (-15 ) ] + 120
= 0 + 0 + 120
= 120
c, 50 + [ 50 - ( 2² . 15+2².5)
= 50 +[ 50- ( 4 . 15 + 4 . 5)
= 50 + [ 50 -( 60 + 20 )]
= 50 + [ 50 - 80 ]
= 50 + ( -30 )
= 20
d , 306 - { [ 144 + |13²-7|:9] }-200
= 306 - {[ 144 + |169-7| : 9 ]} - 200
= 306 - {[ 144 + |162| : 9 ]} -200
= 306 - {[ 144 +162 :9 ]} - 200
= 306 - {[ 144 + 18 ]} - 200
= 306 - 162 - 200
= 144 - 200
= -56
