## Four Digit Subtraction

#### Aligned To Common Core Standard:

**General Operations** - Operations

How do Computers Subtract Numbers? The original purpose of the computer was to solve complex problems. However, what happens inside the technology? You must know that computers understand problems in the form of binary numbers. Therefore, first, they convert both numbers into their binary equivalent. However, to subtract binary numbers, you need to learn 1's and 2's compliment. Let's solve the problem with an example. You need to solve 7 - 4. Firstly, you will need to convert 7 and 4 into their binary equivalent, which is 0111 and 0100, respectively. Now, to subtract a binary number, we need to perform 1's compliment, which means we will have to switch the bits (i.e., 0 to 1 and vice versa) to 1011. The next step is to add 1 to the converted bits to make it 1011 + 1 which is 1100. Now, you can add this with the binary equivalent of 7, which is 0111 + 1100, and the answer is 10011. You can now neglect the leftmost 1 and the answer is 0011, whose decimal equivalent is 3. These worksheets and lessons help students learn how to find the difference between numbers that are composed of four digits.

### Printable Worksheets And Lessons

- Getting Hooked Step-by-Step Lesson- It takes a few pages to explain this one.
- Guided Lesson - I like to space out the numbers within the integer well so students can spatial recognize it better.
- Guided Lesson Explanation - Three problems, three pages of explanation. They should have a solid grasp of the concept after this one.
- Practice Worksheet - I have to pat myself on the back for putting this one all together on one page.
- Matching Worksheet - Big digits make for big differences.

#### Homework Sheets

No big frills here. Straight horizontal differences for you to practice with.

- Homework 1 - We subtract from right to left digit.
- Homework 2 - You will need to borrow several times here.
- Homework 3 - We cannot subtract a bigger number from a smaller number. You can, but you will learn that down the road.

#### Practice Worksheets

We keep it all together using the same rhythm and flow given off by the homework sheets.

- Practice 1 - A little less borrowing is found here.
- Practice 2 - Drop down the values to remove doubt.
- Practice 3 - Subtract the values vertically.

#### Math Skill Quizzes

These all follow the same standard as all the previous sheets. This is a popular quiz topic.