19/21 - 4/12 (4/12 = 1/3) = 12/21
Convert the 1/3 into 7/21 and subtract.
19/21 - 2/7 = 19/21 - 6/21 = 13/21
21/19 = 12/19
-19
2/3 - 4/7 = 14/21 - 12/21 = 2/21
minus 21 think of it as 12+9 which equals 21 then just whack a minus sign infront
2 minus -19 is 21.
1 minus 11/21 = 10/21
13/21 - 7/21 = 6/21 Sorry, DJ, 4 over 7 = 12/21 so answer is 5/21
12/5 − 7/8 = 21/40
16/21 minus two equals -1 5/21
The variance of 29 21 12 19 19 = 37
9