When doing DIY or cooking (taking measurements).
When we make random purchases of anykind and need to budget
Balancing a cheque book
Cooking and baking (using measurements)
Taking medications (using measurements)
Keeping track of debt or even incurring debt
Understanding a gas gage in a vehicle
Understanding distances
Measuring things or understanding how things will 'fit' in our home (like for example: Measuring for a new living room carpet)
Paying cash for an purchased item so you can keep track of your change back
Telling time. Measuring pet food. Counting calories or carbs. Counting guests and place settings and chairs and table space.
When we need to measure, cooking or calculating the money spend in a month.