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Scientific notation

Grade 7 · Math · Free lesson

Hey there! Ready to explore how we write giant numbers easily and connect them to cool math patterns? Let's dive in!

Sometimes we deal with massive numbers in science. To make them easier to read, we use a shortcut called scientific notation. We write a number as a single digit followed by a decimal, multiplied by ten to a power.

Let us look at the word 'notation'. It comes from the Latin root 'notare', which means 'to mark or write down'. So, scientific notation is just a special way to write down big numbers!

Root Word: Notare Means: "To mark or write down" Notation = A Writing System

We can also see math in action with direct variation. This is when two quantities change together at a constant rate. For example, if you buy more items, the total cost goes up by the exact same multiplier every time.

X (Input) Y (Output) Direct Variation: y = kx
✏️ Worked example

A spaceship travels at a direct variation speed. It covers 300,000 meters in 10 seconds. Write this equation, find the constant rate, and write the constant rate in scientific notation.

  1. Identify the direct variation equation form: y = kx, where y is distance and x is time.
  2. Substitute our known values into the equation: 300,000 = k * 10.
  3. Solve for the constant rate (k) by dividing both sides by 10: k = 30,000 meters per second.
  4. Now, convert the constant rate of 30,000 into scientific notation.
  5. Place the decimal after the first digit to get 3.0, then count 4 spaces to the right to reach 30,000.
  6. Write the final scientific notation answer: 3.0 * 10⁴.
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