=3+360

=363

2.9000÷72×( 1.25×0.7×8)

=9000÷72×7

= 125×7

=875

Three. 6 1-( 1.25+2.5×0.7)

=6 1-3

=58

Four. [( 10-0.8)+9.85]-2 ÷ 0. 125

= 19.05-2÷0. 125

= 19.05- 16

=3.05

1, offline calculation, that is, recursive calculation, requires a series of numbers to be calculated step by step. Calculate multiplication and division first, then addition and subtraction. In the successive calculation of multiplication and division, it should be calculated from left to right. Among the four operations, addition and subtraction are called primary operations, and multiplication and division are called secondary operations.

The main thing to master is to remember to calculate multiplication and division first, and then add and subtract. In the successive calculation of multiplication and division, it should be calculated from left to right. When you encounter parentheses, you must first calculate the inside of parentheses.

3. In the process of separation, the operation sequence line should be drawn according to the operation sequence, and the "three checks" should be done well. First, check whether the numbers and symbols copied from books to exercise books are correct. Second, check whether the numbers and symbols copied from horizontal to vertical are copied correctly. Third, it is necessary to check whether the draft is copied vertically, horizontally, and whether the decimal point position is correct or not.