Excuse me while I whip out my Casio fx-82 super fraction calculator.

OK so as everyone is splitting the bill equally you can calculate the amount of tip you will be leaving before you split it four ways, rather fiddling about with it afterwards.

First off, you need to calculate what 15 per cent of 64 dollars is. To do this multiply 64 by 0.15 (that’s 15/100). This gives you the result of 9.6.

Add this figure (9.6) to the 64 dollars. This should give you the figure of $73.60. Now you can divide it equally amongst the four of you so that’s 73.6/4 = 18.4.

You would each pay $18.40 if the bill was $64.00 after tax and you want to leave a 15 per cent tip and to split the bill equally between the four of you. If you want to split the bill differently you calculate the percentage for each person individually.

If you’ve got an iPhone, there’s an app for this very conundrum (www.apple.com/webapps/calculate/tipcalculatorforiphone.html)

OK so as everyone is splitting the bill equally you can calculate the amount of tip you will be leaving before you split it four ways, rather fiddling about with it afterwards.

First off, you need to calculate what 15 per cent of 64 dollars is. To do this multiply 64 by 0.15 (that’s 15/100). This gives you the result of 9.6.

Add this figure (9.6) to the 64 dollars. This should give you the figure of $73.60. Now you can divide it equally amongst the four of you so that’s 73.6/4 = 18.4.

You would each pay $18.40 if the bill was $64.00 after tax and you want to leave a 15 per cent tip and to split the bill equally between the four of you. If you want to split the bill differently you calculate the percentage for each person individually.

If you’ve got an iPhone, there’s an app for this very conundrum (www.apple.com/webapps/calculate/tipcalculatorforiphone.html)