1.67 ×21 ＋18 ×21 + 85 ×792.375 ×480 + 6250 ×48 3.321 ×81 + 321 ×194.222222 ×999999 5.333333 ×3333336.654321 ×909090 +654321 ×909097.34 ×3535 －35 ×3434 8.345345 ÷15015 9.75 ×45 + 17 ×...