In fact losing 10% of a budget equates to a fairly radical rationalization of government spending, large increases in taxation, increased indebtedness, or a combination of the three. I suspect that one of the first things to go would be Quebec's universal child daycare programme for which the users pay a maximum daily rate of $20.00 for families with a combined income greater than CAN$155,000.00 ($7.30 per day for families with a total income less than CAN$50,000.00).10% of a budget is not chicken-feed. Many businesses run at or under 10% profit margin, for example. Lose 10% of your budget, and the thing can collapse.
Of course, a government is not a business. So, consider what happens if you lose that 10% - it means either having to cut 10% of everything, or cut a lot more of some things, and not others. When you start talking about essential services, this can be highly problematic.