25% of 70 is 17.5. This can be calculated by multiplying 25/100 with 70, which gives (25/100)70 = (2570)/100 = 1750/100 = 17.5. Another way to calculate it is by dividing 70 into 100 equal parts and taking 25 of those parts, which gives 17.5. Therefore, 25% of 70 is 17.5.