SAT Practice Exam

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Scientific Notation

If 0.008491 = 8491 x 10^t, what is the value of t?

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Answer
Problems like this involve decimal shifting. Since 0.008491 is less than 8491, we need to shift our decimal place to the left

Decimal Shift Step 1

Shifting the decimal place 1 place(s) to the left, we get 849.1

Decimal Shift Step 2

Shifting the decimal place 2 place(s) to the left, we get 84.91

Decimal Shift Step 3

Shifting the decimal place 3 place(s) to the left, we get 8.491

Decimal Shift Step 4

Shifting the decimal place 4 place(s) to the left, we get 0.8491

Decimal Shift Step 5

Shifting the decimal place 5 place(s) to the left, we get 0.08491

Decimal Shift Step 6

Shifting the decimal place 6 place(s) to the left, we get 0.008491

Shifting the decimal place left signifies a negative power, so our answer is t = -1 x 6 = -6

Writing this out in scientific formation using our answer, we get

0.008491 = 8491 x 10^-6