What number is greater 0.3 or 0.21?

To determine which number is greater between 0.3 and 0.21, we compare the digits place by place starting from the left. In this case, the first digit after the decimal point is 3 in 0.3 and 2 in 0.21. Since 3 is greater than 2, 0.3 is greater than 0.21.