20
15 and 4 are the factors of 120 that add up to 19.
you dont cuz your trying to make 20 or 19 out of an 8 and 3 if u calculate it 8+1+1+1=11
42 - 22 + (6 - 5)*(-1) = 20 + 1*(-1) = 20 - 1 = 19
21 In Roman numerals is XXI. To find any number you just put something on the end to add ( Like 21 would be 20 "XX" plus 1 "I" = XXI "20+1)And to subtract you add in fron(19 would be I "1" taken away from XX "20" = IXX "20-1"). Make any sense?
1 add 4 is 5 and 2 add 3 make 5. 5 add 5 make 10 so 2 x 10 is 20
Since 19 is a prime number, it only has two factors - 1 and 19.
18. 1 and18 add to 19, 2 and 9 add to 11, and 3 and 6 add to 9.
-4 x 5 = -20 and -4 + 5 = 1.
19 + 1 = 20
Subtract a negative 1. 19 - (-1) = 20
20 - 19 = 1