This is because 25%= 25/100, and that reduces to 1/4. Also, whenever it says something OF something, it means to multiply. In this case, 1/4 OF 1000= 1/4x1000= 250.
*Even though it seems that multiplying will just make the number bigger, when you multiply with a fraction, it actually gets smaller* For example 1/3 of 3= 1/3x3= 1
