=270÷(27×2)

=270÷27÷2

= 10÷2

=5

Simple calculation method:

A simple operation of rounding integers, exchanging them first and then combining them. A number MINUS several numbers in succession is equal to the sum of the minuend. A number divided by several numbers in succession is equal to the product of this number divided.

Several numbers are multiplied and then added separately, and several numbers are multiplied and then subtracted separately. Give the same number and put the rest in brackets. More reduction, more increase, less increase, less decrease.