Memory Refresher
The four basic operations are addition, subtraction, multiplication, and division. Each of their parts have a specific name. Let’s go over each operation and a quick refresher on how to work a problem.
Addition
In addition, numbers added together are called addends. The answer is called the sum.
Always add columns from right to left. In our example, the right column adds to 10. Whenever a column adds to a double digit, carry the first digit to the next column.
Subtraction
In a subtraction problem, the first number listed is known as the minuend. The second number is the subtrahend. The answer is called the difference.
Like addition, you will work subtraction from right to left columns. Also like in addition, sometimes you will need to carry a number. This happens when the digit in the minuend column is smaller than the digit in the subtrahend column. In this case, borrow from the neighboring column.
Multiplication
The first number in a multiplication problem is the multiplicand. The second number, the multiplier, is how many times you are multiplying the multiplicand. The answer is called the product.
Work multiplication problems from right to left. If the multiplier is more than one digit, then starting on the second “working line” of your answer, you add a zero before you start multiplying. In Step 3 of the example below, you see the “working line” has four digits. That is because we added a zero before we multiplied. In Step 4, we put two zeros before multiplying. With each new working line, you would have one additional zero than the last working line. Once, you have your “working lines” complete, you add them together for the final answer (product).
Keep your columns straight so the numbers will be added correctly. It is easy to get off track if you don’t.
Division
A division problem has three parts. The inside number (dividend) is divided by the outside number (divisor). The answer is known as the quotient. If a number is not divided evenly and you are not working it out as a decimal, then the amount left over is called the remainder, which can be abbreviated as “r.” when it is used.
In the image above, it might be easy to determine that 4 goes into 30 seven times. What if you have a larger number? See example below.
- If you don’t know off-hand, how many times 7 can be divided into 108, then take the dividend one digit at a time. Does 7 go into 1? No. Does 7 go into 10? Yes, 7 goes into 10 one time.
- You place a 1 as your quotient, then multiply that number by your divisor, place answer below 10 and subtract. The remaining number is 3.
- Bring down the next number in your dividend, which is 8. Next, determine how many times 7 can be divided into 38. The answer is five times so 5 is the next number in your quotient.
- Again, multiply that by your divisor, place under 38 and subtract. You will have a remaining number of 3, but no other numbers to bring down from the dividend so you are done. The answer is 15 with a remainder of 3.
