First, we need to find 1/4 of 2000 in order to find how many blocks he gave away. To do this, we need to do 1/4*2000 to get 2000/4. This can be simplified to 500 by dividing the numerator and denominator by 4.
Then, we can do 2000-500 to find that he must have had 1500 blocks left.
Hope this helps.