= 1.83*2.5+5.3*2.5+2 1.39*2.5

=2.5*( 1.83+5.3+2 1.39)

=2.5*28.52

=7 1.3

2. 12.5*0.76*0.4*8*2.5

=( 12.5*8)*0.76*(0.4*2.5)

= 100*0.76* 1

=76

3. 1990* 198.9- 1989* 198.8

= 1990* 198.9- 198.9* 1988

= 198.9*( 1990- 1988)

= 198.9*2

=397.8

4.(632*276-524)/(632*275+ 108)

=(632*275+632-524)/(632*275+ 108)

=(632*275+ 108)/(632*275+ 108)

= 1