A mole is composed of 6.022 x 10²³ units. these units could be atoms making up an element or molecules making up a compound.
In this case 1 mol of rice would be composed of 6.022 x 10²³ rice grains
the value given is 3.87 x 10²² grains of rice. Since we have to compare 6.022 x 10²³ and 3.87 x 10²² we have to bring them to the same exponent of 10.
so lets convert 6.022 x 10²³
in 6.022 x 10²³ can be rewritten as 6.022 x 10¹ x 10²² since we need the exponent of 10 to be 22
then 6.022 x 10 = 60.22
Therefore it can be written as 60.22 x 10²²
Now we can compare 3.87 x 10²² and 60.22 x 10²²
since exponent of 10 is equal , we have to compare the figures 3.87 and 60.22
since 3.87 < 60.22
we can see that 3.87 x 10²² is less than the number of rice grains that would be make up a mole.
therefore the number of rice grains is less than a mole