a, 277 + 113 + 323 + 87
= ( 277 + 323 ) + ( 113 + 87 )
= 600 + 200
= 800
b, 185 + 434 + 515 + 266 + 155
= ( 185 + 515 ) + ( 434 + 266 ) + 155
= 700 + 700 + 155
= 1400 + 155
= 1555
c, 8 . 12 . 125 . 2
= ( 125 . 8 ) . ( 12 . 2 )
= 1000 . 24
= 24000
d, 4 . 36 . 25 . 50
= ( 4 . 25 ) . ( 36 . 50 )
= 100 . 1800
= 180000
a, 277 + 113 + 323 + 87
= ( 277 + 323 ) + ( 113 + 87 )
= 600 + 200
= 800
b, 185 + 434 + 515 + 266 + 155
= ( 185 + 515 ) + ( 434 + 266 ) + 155
= 700 + 700 + 155
= 1400 + 155
= 1555
c, 8 . 12 . 125 . 2
= ( 125 . 8 ) . ( 12 . 2 )
= 1000 . 24
= 24000
d, 4 . 36 . 25 . 50
= ( 4 . 25 ) . ( 36 . 50 )
= 100 . 1800
= 180000