=8 + 3/4 - (0.35 - 4/ 13) - 4 - 5/8

=4 + 6/8 - 5/8 - (7/20 - 4/ 13)

=4+ 1/8 - 7/20 + 4/ 13

=4+ 5/40 - 14/40 + 4/ 13

=4 - 9/40 + 4/ 13

=4 - 1 17/520 + 160/520

=4 + 43/520

=4 43/520

Two. 1999 * 1999-2000 * 1998

= 1999? - ( 1999+ 1)( 1999- 1)

= 1999? - 1999? + 1

= 1

Three. (1 and 1/4+2 and 5/6)÷( 1 and 1/4*0.8-0.3)

=(5/4 + 17/6) ÷(5/4*4/5 - 0.3)

=( 15/ 12 + 34/ 12)÷( 1-0.3)

=49/ 12 ÷ 0.7

=49/ 12 ÷ (7/ 10)

=49/ 12 × ( 10/7)

=35/6

=5 5/6

Four. [2/3+ 1 and 2/3 *(5.4-2.7)]> 3 and 4/9

=(2/3 + 5/3 *2.7)÷(3 1/9)

=(2/3 + 4.5)×(9/3 1)

=(2/3 + 9/2)×(9/3 1)

=(4/6 + 27/6)×(9/3 1)

=(3 1/6)×(9/3 1)

=3/2

= 1 and 1/2

Verb (abbreviation of verb) (2890+5/6+7/8+9/10) ÷ (5/6+7/8+7/10)

=(2890+ 1- 1/6 + 1 - 1/8 + 1 - 1/ 10)÷( 1- 1/6 + 1 - 1/8 + 1 - 3/ 10)

=(2893 - 20/ 120 - 15/ 120 - 12/ 120)÷(3 - 20/ 120 - 15/ 120 - 36/ 120)

=(2893 - 47/ 120)÷(3 - 7 1/ 120)

=(2893× 120 - 47)÷(3× 120 - 7 1)

=(2893× 120 - 47)÷ 289

=(2890× 120 +360 -47)÷ 289

=(2890× 120 +289)÷ 289

= 1200+ 1

= 120 1