3.8+4.29+2.71+6.2 12.5—0.78—3.22 12.8×99+12.8 1.25×3.2×2.5 12.6×101—12.6 38.5÷2.5÷0.4 6.7×10.1 6.5×101 4.85×98 1.2×2.5+0.8×2.5 28×17.5—28×7.5 4.8×12.56/7＋2/15＋1/7＋13/15 19/21＋5/7...