Decimals - HSPT Math

To subtract decimals you place the first decimal over the top of the other aligned by the decimal point. If there are no numbers after a tens, hundredths, or thousandths place or further to the right of the decimal just add a zero in the required areas.

For example becomes

Then go through each place and subtract the top number by the bottom number. Subtract the numbers in each place like you would any number.

The example we are working with will look like this

The answer after subtraction is

Rewrite the decimal as a fraction and subtract:

Reduce this:

Add the first two numbers, making sure you align the decimal points in the addends and the sum:

Now subtract the third number, making sure you again align the decimal points:

First, combine the positive decimals, which gives you .

Then, you can subtract that from , but remember that your answer is negative since it's a .

Your answer is .

Simplify the sum by taking the least common denominator, which is 12:

Divide 13 by 12:

Nine tenths is equal to 0.9; nineteen thousandths is equal to 0.019. Add them, rewriting 0.9 as 0.900:

To add decimals, first add zeros to the necessary terms so they all have the same number of places to the right of the decimal point.

Now, temporarily drop the decimal and add the numbers as if they were whole numbers.

Finally, add the decimal place back in, in the same place you removed it from. In this case, we originally modified our numbers so they all had 3 numbers to the right of the decimal, so we will add the decimal back to the exact same place. Thus, our answer is:

Rewrite the problem so that the tenths, hundredths, and thousandths digits align. Use zeros as placeholders and solve.

Ensure that each digit is added to the correct digit.

Add three zeros at the end of as placeholders.

Add the tenths place with the tenths place (in this case ), hundredth place with the hundredth place (in this case ) , thousandth place with thousandth place (in this case ), and ten thousandth place with ten thousandth place (in this acase )

Add the placeholder for the hundredths place after .

Rewrite the problem:

Add the hundredths place.

Add the tenths place.

Combine the numbers.

The decimal place is two places from the right.

The correct answer is:

Be careful not to misalign and add the wrong digits. Add placeholders to the end of the decimals so that we can see the tenths and hundreds places.

Add the numbers in the hundredth place.

Add the numbers in the tenths place.

Add the ones digits.

Combine the numbers.

The answer is:

The starting amount of slices is out of which is or of the whole pizza.

The other slices that someone ate is half the whole pie or .

So to find the remaining amount you must subtract from which gives you a quarter or .

,

so

.

If

, then

First you want to add up your hundredths places to get

.

Then you do the same for the tenths places to get

.

Finally, put them together to get .

The tenth's place is the position one unit to the right of the decimal point. In this case, that is the 7.

After identifying the position, we need to determine if this number remains 7 or if we need to round it up to 8. If the number to the right of the tenth's place is 4 or lower, then our number will remain 7. If it is 5 or greater, then we will round the 7 up to 8.

In this case, the number is indeed 5, so our tenth's place becomes 8. All numbers to the left of the tenth's place will remain the same.

The tenth's place is the position one unit to the right of the decimal point. In this case, that is the 7.

After identifying the position, we need to determine if this number remains 7 or if we need to round it up to 8. If the number to the right of the tenth's place is 4 or lower, then our number will remain 7. If it is 5 or greater, then we will round the 7 up to 8.

In this case, the number is indeed 5, so our tenth's place becomes 8. All numbers to the left of the tenth's place will remain the same.

To subtract decimals you place the first decimal over the top of the other aligned by the decimal point. If there are no numbers after a tens, hundredths, or thousandths place or further to the right of the decimal just add a zero in the required areas.

For example becomes

Then go through each place and subtract the top number by the bottom number. Subtract the numbers in each place like you would any number.

The example we are working with will look like this

The answer after subtraction is

Rewrite the decimal as a fraction and subtract:

Reduce this:

Add the first two numbers, making sure you align the decimal points in the addends and the sum:

Now subtract the third number, making sure you again align the decimal points: