Summing up the method of math rounding

Rounding off Decimal rounding: Math.floor (2) =2
Rounding off Decimal rounding: Math.floor (2.1) =2
Rounding off Decimal rounding: Math.floor (-2.1) =-3
Rounding off Decimal rounding: Math.floor (-2.5) =-3
Rounding off Decimal rounding: Math.floor (2.9) =2
Rounding off Decimal rounding: Math.floor (-2.9) =-3
Summary: Math.floor (x) = largest integer less than x

Rounding off Decimals: Math.ceil (2) =2
Rounding off Decimals: Math.ceil (2.1) =3
Rounding off Decimals: Math.ceil (2.5) =3
Rounding off Decimals: Math.ceil (-2.5) =-2
Rounding off Decimals: Math.ceil (2.9) =3
Rounding off Decimals: Math.ceil (-2.9) =-2
Summary: Math.ceil (x) = smallest integer not less than X

Rounded rounding: Math.Round (3.1) 3
Rounded rounding: Math.Round (3.5) 4
Rounded rounding: Math.Round (-3.1)-3
Rounded rounding: Math.Round (-3.5)-3

Summary: Math.Round (x) = Math.floor (x+0.5) (rounding in mathematical sense)

Rounded rounding: Math.rint (2) =2
Rounded rounding: Math.rint (2.1) =2
Rounded rounding: math.rint (-2.5) =-2
Rounded rounding: math.rint (2.5) =2
Rounded rounding: Math.rint (2.9) =3
Rounded rounding: Math.rint (-2.9) =-3
Rounded rounding: Math.rint (-2.49) =-2
Rounded rounding: Math.rint (-2.51) =-3

Special case: Math.rint ()
1. If the parameter itself is an integer, it returns itself.
2. If it is not a number or infinity or plus or minus 0, the result is itself

Summary: Floor is rounded down, ceil upward, round and rint rounded, rounded with absolute values, and then added with symbols, when encountered. 5. Take even that.

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Summing up the method of math rounding