▁sh í ) ▁which ▁literally ▁means ▁" two ▁ten ". ▁Equ ival ents ▁exist ▁for ▁ 3 0 ▁and ▁ 4 0 ▁( ▁and ▁ ▁respectively : ▁Mand arin ▁s à ▁and ▁x ì ), ▁but ▁these ▁are ▁more ▁s eld om ▁used . ▁This ▁is ▁a ▁historic ▁rem nant ▁of ▁a ▁v iges imal ▁system . ▁ ▁Although ▁Kh mer ▁numer als ▁have ▁represented ▁a ▁decimal ▁position al ▁notation ▁system ▁since ▁at ▁least ▁the ▁ 7 th ▁century , ▁Old ▁Kh mer , ▁or ▁Ang kor ian ▁Kh mer , ▁also ▁possessed ▁separate ▁symbols ▁for ▁the ▁numbers ▁ 1 0 , ▁ 2 0 , ▁and ▁ 1 0 0 . ▁Each ▁multiple ▁of ▁ 2 0 ▁or ▁ 1 0 0 ▁would ▁require ▁an ▁additional ▁stroke ▁over ▁the ▁character , ▁so ▁the ▁number ▁ 4 7 ▁was ▁constructed ▁using ▁the ▁ 2 0 ▁symbol ▁with ▁an ▁additional ▁upper ▁stroke , ▁followed ▁by ▁the ▁symbol ▁for ▁number ▁ 7 . ▁This ▁suggests ▁that ▁spoken ▁Ang kor ian ▁Kh mer ▁used ▁a ▁v iges imal ▁system . ▁ ▁Th ai ▁uses ▁the ▁term ▁ ▁( yi ▁s ip ) ▁for ▁ 2 0 . ▁Other ▁multi ples ▁of ▁ten ▁consist ▁of ▁the ▁base ▁number , ▁followed ▁by ▁the ▁word ▁for ▁ten , ▁e . g . ▁ ▁( sam ▁s ip ), ▁lit . ▁three ▁ten , ▁for ▁thirty . ▁The ▁y i ▁of ▁y i ▁s ip ▁is ▁different ▁from ▁the ▁number ▁two ▁in ▁other ▁positions , ▁which ▁is ▁ ส อ