简便计算为3.72×3.5+6.28×3.5＝3.5×(3.72+6.28)＝3.5×10＝35
3.72*3.5+6.28*3.5=3.5*（3.72+6.28）=3.5*10=35
3.72x3.5+6.28x3.5=（3.72+6.28）x3.5=10x3.5=35
