# Multiplying Scientific Notation

How to solve multiplying numbers in scientific notation problems: examples and their solutions.

## Example 1

Multiply the blue parts and the red parts separately.

Product of powers (red)

2.15 × 1.98 is 4.2570.

But both 2.15 and 1.98 has 3 significant digits.

So round 4.257 to 3 significant digits: 4.26.

Rounding:

0-4 → round down

5-9 → round up

## Example 2

Multiply the blue parts and the red parts separately.

Product of powers (red)

8.73 × 9.01 is 78.6573.

So, by rounding, it'll be 78.7.

But 78.7 is not in this interval:

1 ≤ 78.4 < 10.

So change 78.7 to 7.87 × 10.

And multiply this 10 and 10^{6}.

So the answer is 7.87 × 10^{7}.