Can someone explain the maths here?

Interest example: if you save £300 every month for 12 months and qualify for the 5% interest rate, you’ll earn approximately £97.50 interest (gross).

So however I work it out, I can’t get **£97.50**.

300 x 12 = 3600. 5% of 3600 **= £180**

5% of 300 = 15 x 12 **= £180**

https://www2.firstdirect.com/1/2/savings-and-investments/savings/regular-saver-account