For example, a purchase of 100 euros will be shown on your statement as:
5 June 2017, 100 euros @ 1.140440 euros, £87.69 (meaning that 1.140440 euros= £1.00, so 100 euros divided by 1.140440 = £87.69)
100 euros @ the rate of exchange for the euro that is equivalent to £1.00, on the date your transaction was processed by Visa (e.g. 5 June 2017), which may be different from the date on which you made the transaction. See the FAQ: What is the "processing date" for my transaction above for more information.