19/42 x 5/5 = 95/210
13/70 x 3/3 = 39/210
95/210 + 39/210 = 134/210
134/210 = 67/105
13/42
18/35 + 13/42 = 1211/1470 or 173/210
13/14 + 5/6 = 39/42 + 35/42 = 74/42 = 37/21 or 116/21
18/35 + 13/42 = 108/210 + 65/210 = 173/210
13 + 42 = 55
-55
42+(-29) = 13
105.
(7 x 6) + (7 x 13) = 7 x 19 = 133
12/70 - 19/42 = 0.17142 - 0.45238 = -0.28096
42 over 26 can be simplified as 21 over 13
13/42 = 0.3095238 recurring (that is, 0.3095238095238...)