For example, π is rounded off, leaving 3. 14. But sometimes you can use "one-in method" and "tail-out method" instead of rounding. The rounded fourth house is: 1, 2, 3, 4, and the five-fold house is: 5, 6, 7, 8, 9.
"Rounding" method:
Looks like one more digit than the reserved number. The number of digits in this number is "5" or greater. If the number of digits on this digit is "4" or less, discard it, such as 6.56, and keep one decimal place, which is 6.6. And 6.54, one decimal place is 6.5.
When taking decimal divisor, if the highest digit of mantissa is less than 4, the mantissa shall be removed; If the most significant digit of the mantissa is 5 or more, the mantissa is discarded and "1" is input in its previous digit. This method of taking the divisor is called rounding.
"Nine Chapters Arithmetic" also adopts the method of "rounding". When using the proportional method to find the vehicles that should be dispatched in each county, because the vehicles are integers, the calculation results are rounded off.