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Subtraction

Introduction

Subtraction is like taking away toys from your toy box. If you have 5 toys and you give 2 to your friend, how many toys do you have left? You’d count and find out you have 3 toys left. That’s subtraction!

Reasons to Use

Subtraction helps us figure out how much is left when something is taken away. It’s useful when you need to know how much money you have after buying a toy or how many apples are left after giving some to your friend.

Out in the Wild!

  • Shopping: If you have £10 and buy a toy for £4, subtraction helps you know you have £6 left.
  • Games: If you score 15 points and lose 3 points, subtraction tells you your new score is 12 points.
  • Cooking: If a recipe needs 5 cups of flour and you only have 2 cups, subtraction helps you know you need 3 more cups.

Examples

Beginner:

Problem: 8 – 3

  • Step 1: Imagine you have 8 candies.
  • Step 2: Give 3 candies to your friend.
  • Step 3: Count how many candies you have left.
  • Answer: 5 candies.

Intermediate:

Problem: 42 – 18

  • Step 1: Write the numbers in columns, like this:

     
      42
    - 18

  • Step 2: Subtract the units (rightmost) column: 2 – 8. We can’t do this because 2 is smaller than 8. So, we need to borrow from the tens column.

  • Step 3: Borrow 1 ten from the tens column. The 4 in the tens column becomes 3, and the 2 in the units column becomes 12.

        3  12

    - 1 8

  • Step 4: Now subtract 12 – 8 = 4.

  • Step 5: Subtract the tens column: 3 – 1 = 2.

  • Answer: 24.

Expert:

Problem: 604 – 257

  • Step 1: Write the numbers in columns:

     604
    - 257

  • Step 2: Subtract the units column: 4 – 7. We can’t do this, so we borrow from the tens column. But the tens column is 0, so we borrow from the hundreds column instead.

  • Step 3: The 6 in the hundreds column becomes 5, the 0 in the tens column becomes 10, and the 4 in the units column becomes 14.

      5 10 14
    - 2  5  7

  • Step 4: Subtract the units column: 14 – 7 = 7.

  • Step 5: Subtract the tens column: 9 – 5 = 4 (since we borrowed 1, the 10 becomes 9).

  • Step 6: Subtract the hundreds column: 5 – 2 = 3.

  • Answer: 347.

Troubleshooting Tips

  • Forgetting to Borrow: Always check if the number on top is smaller than the number below. If it is, remember to borrow from the next column.
  • Misalignment: Ensure numbers are aligned correctly in columns, with units under units, tens under tens, and so on.
  • Rushing: Take your time to avoid simple mistakes.

Also known as...

You will also find questions that may use other words but will mean the same thing. These all mean Subtract

  • Minus
  • Take away
  • Subtract
  • Decrease
  • Remove
  • Less
  • Difference

Where else is this Used?

Sometimes, when you subtract, you end up with a negative number. This happens when you take away more than you have. For example, if you have 3 apples and someone takes 5, you’ll have -2 apples, which means you owe 2 apples. Negative numbers are like telling us we have less than zero.

Memory Tips

  • Rhyme Time: “More on the floor, go next door; get ten more.”
  • Visual Aids: Use a number line to jump backward when subtracting.
  • Finger Tricks: Use your fingers to count backward for small numbers.

Game Time!

What You Need: Paper, pencils, and dice.

How to Play:

  1. Each player rolls two dice and subtracts the smaller number from the larger number.
  2. Write down the subtraction problem and solve it.
  3. The first player to solve 10 problems correctly wins!

Enjoy your Super Subtraction Adventure and become a subtraction superhero!

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