First, write the number as a single digit times a power of 10.
20 times
Practice makes perfect
Here we have two lengths of two different plant cells.
Length of Plant Cell A (m)
Length of Plant Cell B (m)
8 * 10^(- 5)
0.000004
We want to decide how many times greater is the length of plant cell A than the length of plant cell B. To do this, we first need to rewrite the plant cell B's length.
Rewriting Plant Cell B's Length
Before we can compare the length of the two cells, we first need to write the length of plant cell B as a single digit times a power of 10.
0.000004
For that, we will rewrite the number as its greatest place value times a power of 10. To find the exponent, we need to count the zeros in the number.
.000004
We see that there are 6 zeros. Now, recall how the sign of the exponent changes for different numbers.
Numbers Greater Than 1
Numbers Less Than 1
positive (+)
negative (-)
Since 0.000004 is less than 1, the exponent is negative. This means that the exponent of 10 is - 6. We now have everything we need to rewrite our number.
0.000004 = 4 * 10^(- 6)
The length of plant cell B is 4 * 10^(- 6) meters.
Comparing Lengths
Now, we want to find how many times greater the length of plant cell A is than the length of plant cell B. Let's review what we have found so far.
Length of Plant Cell A (m)
Length of Plant Cell B (m)
8 * 10^(- 5)
4 * 10^(- 6)
We need to divide the length of plant cell A by the length of plant cell B. Let's do it!
