@ @pbjïØ Üa@ @SV 7 . 3 × 9 = 27 7 .2 . 2 ×27 = 54 .7 () . 777 1000 1 7 3 . 243 + 54 + 3 = 300 () .A ≠ 0 ABC . . 9 ×10 ×10 = 900 . 900 = 450 () 2 1000 20 . 5 . zyx