a)17.85+15.17-120
=17.(85+15)-120
=17.100-120
=1700-120
=1580
b)37.24+37.76+63.79+21.63
=37.(24+76)+63.(79+21)
=37.100+63.100
=(37+63).100
=100.100
=10000
c)69.113-27.69+69.14+31
=69.(113-27+14)+31
=69. 100 +31
= 6900 +31
= 6931
d)5.$6^{2}$ -18:3
=5.6.6-6
=(5.6-1).6
= 29 .6
= 174
e)$5^{3}$ .35+$4^{3}$ .7
=$5^{3}$ .5.7+$4^{3}$ .7
=($5^{4}$ +$4^{3}$ ).7
= 689 .7
= 4823
g)3⁶.3²+2.81²
=6561+13122
=19683
h)(6⁴.8⁴):12³
=$48^{4}$ :$12^{3}$
=3072
i)(x⁵.y²)²:y⁴(y≠0)
=$x^{10}$ .$y^{4}$ :$y^{4}$
=$x^{10}$
