355+260+140+245 102×99 645-180-245
382×101-382 3500÷14÷5 175×56+25×56
(a+b)+c=+(+)
a-b-c=-(+)
(a+b)×c=×+×.
a÷b÷c=÷(×)
3.06-[1.8×(2.41-1.91)]