a) [( -140 ) + ( -280 ) - ( -264 ) - 784 ]
= [ -140 - 280 + 264 - 784 ]
= [( -140 - 280 ) + ( 264 - 784 )]
= ( -420 - 520 )
= -940
b) [ 68 - ( -247 )] . [( 824 - 962 ) - ( 143 + -268) + ( -842 - ( -241) - 196 ]
= ( 68 + 247 ) . [ ( -138 ) - ( -125 ) + ( -601 ) - 196 ]
= 315 . [ -138 + 125 - 601 - 196 ]
= 315 . ( -810 )
= -255150
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