delta tu add= (1/90) -(1/325)... =0.01111111111111111... -0.003076923077... =bout 0.0034187923... but teech probablee wont like this eezee wae... gotta duit frakshun wae... first, yu gotta get LCM(90,325)=5850... then konvert em: (1/90)=65/5850... (1/325)=18/5850, so differ=(65-18)=47/5850=0.008034188034