To compare the value of SGD and the value of SAR the currency pair SGD/SAR is used and this means that we want to know how much of SAR we need to buy one SGD. That amount is currently in 2.81090.
Going into terminology, in this case SGD is the transaction currency or base currency therefore the counter or quote currency is SAR.
We are going to see the progress of this currency pair in the last hours since the minimum value that has been found has been 2.80980 and the maximum of 2.81720 y means a percentage of variation of the 0.23000% due to the difference of 0.00640.