A или an: cep, plasticine, paintbrush, chalk, crayon, ink, feltpen, marker, compasses (в мн. ч), alidad, puncher, pencil pot, glue, gluestick, sticker, scotch tape, scissors, stapler, staple remover, correction fluid, correctio...

a cap,a plastic one,a paintbrush, a chalk,a crayon,an ink,a felt pen, a marker,a compasses,an alidads,a punchers,a pensil pots,a glues,a glue sticks,a stickers,a scotch tapes,a scissors,a staplers,a staple removers,a correction fluids,a correction tapes,a paper clips, a drawing pins,a magnets,a calculators,a desk organizers,a maps,a globes,an atlas,an encyclopedia, a spikes,a record books,a colouring books,a folders,a white boards.