3.2×15= 3.2×1.5= 32× =4.8
4.8×13= 4.8×1.3= ×1.3=0.624
×=38.5
×=3.85
385÷=0.385
10000999 1.87×0.951.87
÷ a×1.5a÷ (a>0)