a) 67 + 135 + 33
= ( 67 + 33 ) + 135
= 100 + 135 = 235
b) 8 * 17
= 8 * ( 10 + 7 )
= 8 * 10 + 8 * 7
= 80 + 56 = 136
c) 2 * ( 512 * 50 )
= ( 2 * 50 ) * 512
= 100 * 512 = 51200
d) 4 * 37 * 25
= ( 4 * 25 ) * 37
= 100 * 37 = 3700
e) 277 + 113 + 323 + 87
= ( 277 + 323 ) + ( 113 + 87 )
= 600 + 200 = 800
f) 5 * 25 * 2 * 16 * 4
= ( 5 * 2 ) * ( 25 * 4 ) * 16
= 10 * 100 * 16 = 16000