Evaluate \(3.0\times 10^1 - 2.8\times 10^{-1}\)leaving the answer in standard form

Assessment: WAEC SSCE - General Mathematics - 1998 (Objective) Subject: General Mathematics

Question 1 Report

Evaluate \(3.0\times 10^1 - 2.8\times 10^{-1}\)leaving the answer in standard form
Answer Details
To subtract two numbers in scientific notation, we first need to make sure they have the same power of 10. We can do this by moving the decimal point to the right or left as needed. Starting with \(3.0\times 10^1\) and \(2.8\times 10^{-1}\), we can move the decimal point one place to the left in the first number to get \(3.0\) and two places to the right in the second number to get \(0.028\). Now we have: $$ 3.0 - 0.028 = 2.972 $$ To express the answer in standard form, we need to convert it to the form \(a \times 10^b\), where \(1 \leq a < 10\) and \(b\) is an integer. We can do this by moving the decimal point to get a number between 1 and 10, and counting the number of places we moved it. In this case, we moved the decimal point one place to the left, so: $$ 2.972 = 2.972 \times 10^1 $$ Therefore, the answer is \(2.972 \times 10^1\).

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