Looks like they are dado blades from two different size sets probably an 8 inch and a 6 inch just from the pictures. You should be finding two almost identical blades that those are almost the exact same diameter for each of those sizes.. There actually on most sets is a left and right blade that has a slight offset so that it stacked with those will cut more evenly. Most of the time those dado spaces would not cut exactly even with the outside blades and that is normal. The larger set would be a set for a table saw and the other smaller set might work on some skill saw type saws if the arbor was long enough..