First you round 312 to 310 and then you round 287.6 to 290, which equals, 20. ;)
310
It is 313 because .9 is greater than .5
312
300
When using compatible numbers, we can round 0.97 to 1 and 312 to 300 for easier multiplication. Multiplying 1 by 300 gives us 300. Therefore, 0.97 multiplied by 312 is approximately 300 when using compatible numbers.
312.
312 mm is equal to .312 meters.
312
1,2,3,4,6,8,12,13,24,26,39,52,78,104,156,and 312.
312
312% of 213= 312% * 213= 3.12 * 213= 664.56