Question

The mass of a proton is about 1.7 \times 10^(-24). Write this number in standard notation.

Answer 1

Now we have a negative exponent, which is the opposite of a positive exponent.

If a positive exponent means you're multiplying by 10s and it makes a number bigger by moving the decimal to the right, then

the opposite of this is that a negative exponent means you're dividing by 10s and making the number smaller by moving the decimal point to the left.

 

Examples:

$930 \div 10 = 93$

${\bf930 \div 10} \div 10 = {\bf 93} \div 10 = 9.3$

 

The trick is to recognize that

$930 \div 10$ is the same thing as $930 \times 10^{-1}$

${}\div 10$ and ${}\times 10^{-1}$ mean the same thing.

So, $930 {\bf {}\div 10 \div 10} = 930 {\bf {}\times 10^{-1} \times 10^{-1}} = 930 {\bf {}\times 10^{-2}} = 9.3$

 

For your exercise, ${}\times10^{-24}$ means you'll move the decimal point 24 places to the left, to make the number smaller.