Formulas

Habari! Welcome to the World of Excel Formulas!

Ever felt like calculating your school marks, your monthly budget for data bundles, or even the profit from a small side-hustle takes too much time? Imagine you have a magic assistant who can do all the math for you, instantly! Well, that's exactly what Excel Formulas are. They are the 'spells' that turn your spreadsheet from a boring table into a powerful, automatic calculator. Sawa sawa? Let's begin!

Think of it like this: You have a list of all your expenses for the week - bus fare to town, lunch, airtime, and maybe a movie ticket. Instead of using a calculator (or your head!) to add them up one by one, you can teach Excel to do it for you. And if the price of bus fare changes next week, Excel will update the total automatically! Magic, right?

What Exactly is a Formula?

In the simplest terms, a formula is an instruction you give to Excel to perform a calculation. But there is one very, very important rule you must never forget. It's the golden rule of Excel:

Every single formula must begin with an equals sign (=).

The equals sign tells Excel, "Hey! Wake up! What comes next is a math problem you need to solve." If you forget it, Excel will just think you're typing regular text.

The Building Blocks of a Formula

Every formula is made of a few key parts, just like a good recipe. Let's look at our ingredients:

• The Equals Sign (=): The boss! It always comes first.
• Cell References (e.g., A1, B2, C5): These are the 'addresses' of the cells containing the numbers you want to use. Instead of typing the number 500, you type the address of the cell that has 500 in it, like C2. This is super important!
• Operators: These are the symbols for the math you want to do.

Here are the main operators you will use every day:

+   (Addition)
-   (Subtraction)
*   (Multiplication - we use the star, not 'x'!)
/   (Division)

Here's a small diagram to help you visualize it. Imagine you want to add the value in cell A1 to the value in cell A2.

     A
   +---+
 1 | 50|  <-- This is cell A1
   +---+
 2 | 25|  <-- This is cell A2
   +---+
 3 |   |  <-- We will type our formula here, in A3
   +---+

Your formula in cell A3 would be: =A1+A2

Tupige Hesabu! Let's Do Some Real Calculations

Example 1: The School Canteen Budget

Imagine you have KSh 100 for break time. You buy a smokie for KSh 30 and a soda for KSh 40. How much have you spent? Let's put this in Excel.

Image Suggestion: A vibrant and realistic digital painting of a Kenyan high school canteen during break time. Students are queuing, laughing. One student is happily holding a smokie pasua and a soda. The scene is full of life and bright colours.

1. In cell A1, type Smokie Price. In cell B1, type 30.
2. In cell A2, type Soda Price. In cell B2, type 40.
3. In cell A3, type Total Spent.
4. Now, in cell B3, type your formula. Remember the golden rule!

=B1+B2

When you press Enter, cell B3 will instantly show 70! Now, the best part. If the price of a smokie goes up to KSh 35, you just change the number in cell B1. The total in B3 will update to 75 automatically. You don't have to re-do the math!

Example 2: Your End-of-Term Marks

You've worked hard all term! Let's calculate your total marks for three subjects.

      A              B
   +--------------+-------+
 1 | Subject      | Marks |
   +--------------+-------+
 2 | Maths        |   75  |
   +--------------+-------+
 3 | English      |   82  |
   +--------------+-------+
 4 | Kiswahili    |   78  |
   +--------------+-------+
 5 | Total Marks  |       | <-- Formula goes here!
   +--------------+-------+

In cell B5, you would type the formula to add up your marks:

=B2+B3+B4

Excel has an even faster way for long lists, using a built-in 'shortcut' called a Function. For adding, we use the SUM function. It looks like this:

=SUM(B2:B4)

The colon (:) between B2 and B4 means "everything from B2 through to B4". This is very useful if you have 10 subjects instead of 3!

Example 3: M-Pesa Agent Commission

Let's say your auntie runs an M-Pesa shop. She gets a small commission for every withdrawal transaction. If she does 50 transactions and her commission is KSh 10 for each, how much does she make?

Image Suggestion: A clean, modern M-Pesa agent kiosk in Kenya. A friendly female agent is smiling at a customer. The green and white M-Pesa branding is prominent. The style should be bright and positive.

• Cell A1: Number of Transactions
• Cell B1: 50
• Cell A2: Commission per Transaction
• Cell B2: 10
• Cell A3: Total Commission
• Cell B3 (Your Formula):

=B1*B2

Press Enter, and Excel will show 500. She made KSh 500 in commission!

Common Mistakes (Don't Worry, We All Make Them!)

1. Forgetting the equals sign (=): If you type `B1+B2`, Excel will just show the text `B1+B2`. It won't calculate anything.
2. Using 'x' for multiplication: Always use the star `*`. Excel doesn't understand 'x' for math.
3. Typing numbers directly into the formula: It's tempting to type `=30+40`. But if those numbers change in your cells, your formula won't update! Always use cell references (like `=B1+B2`). It's the professional way!

Your Turn! Zoezi Lako.

Now it's your chance to be the boss of Excel. Open a new sheet and create a simple weekly budget for your transport fare to school or work.

• In Column A, list the days: Monday, Tuesday, Wednesday, Thursday, Friday.
• In Column B, enter how much fare you use each day.
• In cell B6, write a formula to calculate the Total Weekly Fare. Use the SUM function!

You've Done It!

Hongera! Congratulations! You have just learned the most fundamental and powerful skill in Microsoft Excel. Formulas are the engine of every spreadsheet. Remember the Swahili proverb, "Kidogo kidogo hujaza kibaba" (Little by little fills the measure). The more you practice, even with small things, the more confident you will become.

Keep practicing, and soon you'll be solving all kinds of problems with the magic of Excel formulas!