c,26.7x5.6-26.7x4.65
=26.7x(5.6-4.65)
=26.7x0.95
=25
d,3.8x(12.43+4.57)+17x6.2
=3.8x17+17x6.2
=17x(3.8+6.2)
=17x10
=170
e,(23.78-7.26)x3.6+16.52x4.5-8.1x6.52
=16x3.6+16.52x4.5-8.1x6.52
=57+74-52
=79
f)62.92:5.2-4.2x(7-6.3)x3.67-1.2102
=12-2x2.4598
=12-4
=8