Answer
21.31 kg, 21.29 kg , 0.02 kg
Work Step by Step
The upper limit is the measurement + tolerance, that is,
$$
21.30+0.01 = 21.31\ kg
.$$
The lower limit is the measurement - tolerance, that is,
$$
21.30-0.01 = 21.29\ kg
.$$
The tolerance interval = upper limit-lower limit, that is,
$$
21.31\ kg-21.29\ kg=0.02\ kg
.$$
