Simple algorithm of 9 3 / 4-15 * 19-2 / 19

Simple algorithm of 9 3 / 4-15 * 19-2 / 19

Can this be simple?
9 3 / 4-15 * 19-2 / 19
=9+3/4-15*（20-1）-2/19
=9-300+15+57/76-8/19
=-276+49/19
=-276+2+11/19
=-273 and 8 / 19
Have a good time

20-19 + 18-17 + 16-15 + 14-13 + 12-11 + 10-9 + 8-7 + 6-5 + 4-3 + 2-1 =? Simple algorithm
There should be fewer steps, and no such wordiness as (20-19) + (18-17) + (16-15) + (14-13) + (12-11) + (10-9) + (8-7) + (6-5) + (4-3) + (2-1) = 10
Use the fourth grade knowledge

The formula of this problem is = n (the largest number) / 2 = 20 / 2 = 10
Then, according to the normal calculation, 20-19 = 1, 18-17 = 1... There are ten like this, so it's 10 * 1 = 10

A simple algorithm of 19 times 37 + 19 times 36

19 times 37 + 19 times 36 = 19 * (36 + 37) = (20-1) * 74 = 1480-74 = 1406

A simple algorithm of 19 * 36 + 19 * 36 + 19

19*36+19*36+19
=19*(63+36+1)
=19*100
=1900