I assume you want the numbers added together?
In which case, you simply total the numbers together.
8 + 20 + 18 + 21 = 67
If I've assumed wrongly, then more information is needed.
18/20 + 8/20 - 5/20 = 21/20 or 1 and 1/20
4, 6, 8, 9, 10, 12, 14, 15, 16, 18, 20, 21
10 + 8 + 20 + 7 = 10 + 20 + 8 + 7 = 30 + 15 = 45
7/8 of 21 is 18 3/8
18/8 = 22/8 which simplifies to 21/4
what is the mode of the following data 18, 17, 12, 14, 8, 21, 10, 11, 19, 20, 10, 5, 17, 12, 10, 20
18/20 + 8/20 - 5/20 = 21/20 or 1 and 1/20
4, 6, 8, 9, 10, 12, 14, 15, 16, 18, 20, 21
10 + 8 + 20 + 7 = 10 + 20 + 8 + 7 = 30 + 15 = 45
7/8 of 21 is 18 3/8
GCF(20, 18, 8) = 2.
18/8 = 22/8 which simplifies to 21/4
The Least Common Multiple (LCM) for 20 8 18 is 360.
20/8 = 21/2
-7/-8 x -20/-21 = 5/6
12 numbers (including 21). The numbers are 4, 6, 8, 9, 10, 12, 14, 15, 16, 18, 20, 21.
fractions between 8over10 and 5over4 = 17/20, 18/20, 19/20, 20/20, 21/20, 22/20, 23/20, & 24/208/10 = 16/205/4 = 25/20thus fractions between 8/10 and 5/4 = 17/20, 18/20, 19/20, 20/20, 21/20, 22/20, 23/20, & 24/20