We solve this by multiplying the starting value, £4500 , by 1 + {the interest rate expressed as a decimal} , or in this case, 1 + 0.013 . This gives us £4500 x 1.0136 and when we type this into our calculator, we get £4,862.607168... but when dealing with money we only ever work to two decimal places, making this £4862.61