sin a=a/(2R)
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480480: 24-4(81-63):2=19984.
1)81-63=18;
2)18:2=9;
3)4*9=36;
4)480480/24=20020;
5)20020-36=19984.
(22/3-55/8):3/4-(21/4-181/40):29/20=
(176/24-165/24):3/4 - (210/40 - 181/40): 29/20
11/24 *4/3 - 29/40 * 20/29 =
44/72-1/2 = 11/18-9/18= 2/18 = 1/9