I was never good at math. My struggle began in Grade 2 with multiplication tables and culminated in a disastrous introduction to Algebra in Grade 9 that planted me firmly in a desk during the month of July for summer school. The slack was too heavy after that so I downgraded to General Math (the dummy class) and eventually graduated high school with a mark of 55. That was then.The math skills I’ve had to learn as a separated parent and wife of another separated parent would make even Pythagoras proud. It all stems from the 60/40 rule: I pay for 40 per cent of all expenses relating to my two sons while their dad pays 60 per cent; and my husband pays for 60 per cent of all expenses relating to his three daughters while their mom pays 40 per cent. It seems like a pretty basic mathematical formula, but when you’re preparing to send one kid to university, one to high school, one to junior high and two to elementary, it gets complicated. Add to that a host of guitar, dance and gym lessons and there’s a whole lot of scheduling, registering, calculating and cheque writing going on. Like most separated parents with any sort of cost-sharing decree, our 60/40 rule can be applied to all expenses and even the minutia like haircuts, hot lunches and friend’s birthday gifts can get sieved through the formula. And while a plan is necessary when children are being raised in two different homes, I find a level of generosity and willingness to set the math aside is mandatory. The last thing a kid should ever hear is “I already paid my share” or “It’s your (other parent’s) turn to pay.” Kids grow weary of hearing their parents fight about money, and if every hot lunch form becomes a back-and-forth runaround, they’ll likely come to the conclusion that cold sandwiches aren’t so bad.In the end, figuring out the math is the easy part. It’s all the other stuff that gets complicated.Speaking of complicated, there’s a few birthdays around the corner. I’m an old-school mom whose heart would break if I couldn’t spend at least a portion of my kids’ birthdays with them. Fortunately it’s always worked out for me. On the flipside, my husband has his daughters half the time and consequently has them for half their birthdays. This Saturday happens to be the littlest one’s birthday and since it’s our week, we’re planning a party. I invited her mom. This is a new endeavour as relations have been chilly, so to speak, all around and at first blush seems like advanced insanity. But at the end of the day, it’s not my birthday and it’s not my party.We’ll see how it all works out….