2+2+2+2+2= 10 (branch) (each 2 represents a notebook, which means two pencils).

2+2+2=6 (PCs) (3 notebooks equals the price of 6 pencils)

10-6=4 (branch) (total * * * can buy 10 branch, three copies are equivalent to 6 branches, and the rest are 4 branches).

Little monkey Lele bought four pencils.