Doi dau phay cua so A sang ben trai mot hang thi duoc so B, nhu vay so A gap 10 lan so B. Doi dau phay cua A sang ben phai mot hang thi duoc so C, vay thi C gap A 100 lan. C se gap B so lan la: 10*10= 100 [lan] So B la: 259,74:[ 1 + 10 +100 ] =2,34 Vay so A= 2,34*10=23,4 DS:23,4