The number of net carbs (total minus fiber) is the one to look for.
You might need to set a 'goal' for fiber in your fitday account to get it to show the fiber carbs as well as the total carbs in your daily totals so you can work out the net carbs.
Because fitday lists them and shows you that pretty 'pie chart' some people also look at the percentages of fat/protein/carbs which on induction should be something like 65% fat/30% protein/5% carbs, but don't get too 'anal' about them.
They were not a rule set by Dr Atkins in DANDR or any of his other books but were arrived at during a study by Dukes University when they worked out that those percentages 'happened' if you ate according to the induction menus