Add when doing gardening work by counting seeds or seedlings. Count the number of holes and rows you need. For example, if you have five rows with 10 seedlings in each row, you know you need 50 seedlings total.
Calculate how much time it will take to get to a particular location when you are going out. For example, if the location is 25 miles down a 60-mile-per-hour highway, you know it will take about 25 minutes to get there.
Calculate your fuel costs. Find out how much fuel you need to get there and back, along with how much the fuel will cost. For example, if you know your destination is 25 miles away, and your car gets approximately 25 miles per gallon, you'll need two gallons of gas to go there and back. If gas is currently $3.50 per gallon, you know that you need $7 worth of gas to complete your trip.
Keep track of your money using subtraction. Figure out how much you have to spend and save. For example, if you're getting paid $480 this week, and you owe $350 for rent, you know you will have $130 left over.
Figure out how much interest you have to pay on credit cards and loans so you know how much you owe. For example, if you owe $100 on a credit card with 15 percent interest, you pay the company $115 that month. That is, $100 x .15, which equals 15. Add 15 to $100 and you'll have your total of $115.
Figure out how much paint and flooring you need to make sure you have enough but not too much. For example, if your floor is 12 feet by 12 feet, and the tiles are each 12 inches by 12 inches, you know you need 144 tiles to cover your floor, as 12 times 12 equals 144 square feet. Each tile is 1 square foot (12 inches by 12 inches), therefore you need 144 of them to fill the floor.
Measure the right amount of ingredients when baking to get the mixture right. For example, if the recipe calls for two cups of flour and one tablespoon of baking soda, then you know to add one tablespoon of baking soda for every two cups of flour even if you are doubling or tripling the recipe. For a triple recipe, you know that six cups of flower would need three tablespoons of baking soda.
Figure out how much it will cost to buy all the ingredients for a dish to see if you have enough money. For example, if the flour costs $3.50, the sugar $2.75 and the butter $1.25, you know the total is $7.50. If you have $10 in your pocket, you know you have enough.
Break down fractions into decimals, or vice-versa, to complete a recipe. The recipe calls for .75 cups of milk, but your measuring cup only uses fractional measurements such as 1/4, 1/3, 1/2, 2/3, and 3/4. To turn the decimal into a fraction, move the decimal point two places to the right, and make a fraction with the number over 100. In this example, it would be 75 over 100. Reduce to the lowest possible denominator to get 3/4. If the fraction needs to be a decimal, simply divide the top number (numerator) by the bottom number (denominator) to get a decimal.