How to Add Faster Than a Calculator

Calculators are amazing gadgets that do all sorts of calculations. But you can't always find a calculator when you need one, and the occasional dead battery or limited light makes it impossible to operate one. Learn addition tricks that amaze your friends when you can add faster than a calculator can.

Instructions

Difficulty: Moderately Easy

1. Remember that numbers are reversible in addition. For example, 33 + 567 is the same as 567 + 33. Always start with the largest number in order to count less and faster.
2. Round off to the nearest multiple of ten when adding. Multiples of ten are significantly easier to manipulate than numerals that end in 7, 8 or 9. When you add 79 + 19, see both numbers as being one away from multiples of 10 or 80 + 20. You know that the answer to 80 + 20 is 100, so just subtract the 2 that you previously added to the numbers from the final answer.
3. Use the place value of 10 as another way of adding faster when only one of your numbers is close to 10. For example, if you're adding 63 + 28, you know that 28 is just 2 less than 30. When you add 2 to 28 for 30, take 2 off your other number, 63 – 2 = 61. Then add 61 + 30 for an easier equation.
4. Add the ones first. Numbers have place values: ones, tens, hundred, thousands and so on. When you add the ones first, it makes it easier to add on the next place value. Look at 335 + 112. Add the ones, 5 + 2 = 7. Add your ones to the result of the tens place value, in this case, 30 + 10. So far you have 47, and all you have left is to add them to the hundreds place value numbers, 300 + 100 = 400 + 47 = 447.

Tips & Warnings

• Like any skill, addition improves with practice. Find opportunities to practice addition tricks.