As a secondary Math teacher, I  know that Texas Instruments graphing calculators with bright yellow cases are ONLY sold in sets of 10!  This "school-bus" color is NOT available on individual calculators (even by special request) no matter what the seller tells you.  Due to the expense (about $1,200 per set), it's pretty unlikely that a teacher or student would have purchased an entire set out of their own pocket, thus calling into question how the seller gained possession of the item(s).


The faceplate and cover have "School Property" deeply engraved on them, but sellers often position the calculators so the engraving is not visible (as above).  If you're in doubt, ask the seller for more pictures from various angles, especially close-ups of the slide-cover and face-plate.  Don't support the stealing of school calculators!!