Decimals
The decimal system is based on the number 10, both in whole numbers and in partial numbers. Instead of fractions with a line, we have the decimal point. One half (1/2) is 0.5 in the decimal system. In this example, the zero is in the ones place meaning the number is less than one. The 5 is in the tenths place meaning there are 5 tenths. Since there are no other numbers, the way to say this is either "five tenths" or "zero point five."
Let's look at a few rules with decimals:
The decimal point defines the value of the number by ten-fold... if moved one place to the right, the number increases in value by ten. If moved one place to the left, the number decreases in value by ten. The number 3.14 increases ten-fold by making it 31.4, yet it decreases ten-fold if we make the number 0.314
When we have a number that is less than 1, we need to use a leading zero before the decimal point. This reduces errors in transcribing because the zero indicates that a decimal point follows. Without the zero, someone might not notice the decimal point and read the number ten-fold greater than it should be. Writing it as .1 gram could be interpreted as 1 gram, and thus a larger dose that could cause harm to the patient. So, we write it as 0.1 gram
Trailing zeros are not to be used, as they can also cause errors. Don't write 25.0 but write 25 instead. Otherwise, it could be interpreted as 250 on accident
Did you notice the error above? Lorena Barajas, 1st semester nursing student did on Jan 9, 2023!
0.01 x 1000 should be 10, not 100! Great work Lorena!
Do some practice, and don't use a calculator for the problem, but use one to confirm your answers
1000 x 1000 =
1,000,000 Move the decimal over 3 places to the right... 1,000 becomes 1,000,000
5 x 10,000 = (use the 5 as your base and move the decimal point as needed)
50,000 Move the decimal 4 places to the right of the 5... 5 becomes 50,000
1000 x 0.1 = (this one is tricky... either move the decimal point on the 1000 one place to the left, or move the decimal point on the 0.1 three places to the right)
100 Move the decimal of the 1,000 one place to the left... 1,000 becomes 100; or move the 0.1 decimal 3 places to the right... 0.1 becomes 100
0.01 x 0.01 = (tricky again... how many places will you move the decimal point and in which direction?)
0.0001 Move the decimal 2 places to the left... 0.01 becomes 0.0001
0.001 x 1000 =
1 Move the decimal of the 0.001 three places to the right or move the decimal of the 1,000 three places to the left... either way, the answer is 1
1 x 0.001 = (this one is way easier than you might realize)
0.001 Move the decimal of the 1 three places to the left... 1 becomes 0.001; or recall that anything multiplied by 1 needs no calculation.
Now that you are comfortable with decimals, time to round