General rules to add decimal numbers:
Step 1: Line up the decimal numbers one by one.
Step 2: To equalize the number of decimal places by adding zeros at the rightmost side of the decimal number.
Step 3: Start adding from the rightmost digit of the decimal number as the usual addition.
Step 4: Finally, put a decimal point in the answer in the same place as the numbers above it.
Example:
Add \(456.23\) and \(56.026\).
Here, to equalize the decimal places, add zero at the end of \(456.23\).
Therefore, the addition of \(456.23\) and \(56.026\) is \(512.256\).
General rules to add decimal numbers:
Step 1: Line up the decimal numbers one by one.
Step 2: To equalize the number of decimal places by adding zeros at the rightmost side of the decimal number.
Step 3: Start subtracting from the rightmost digit of the decimal number as the normal addition.
Step 4: Finally, put a decimal point in the answer in the same place as the numbers above it.
Example:
Subtract \(94.56\) from \(156.6\).
Here, to equalize the decimal places, add zero at the end of \(156.6\).
Therefore, the answer is \(62.04\).
Estimating sums and differences:
Let's see how to estimate the sums and differences of decimal numbers.
If we add two decimal numbers, their total will always be:
- More than \((\uparrow)\) the sum of just the whole numbers.
- Less than \((\downarrow)\) the sum of the whole numbers plus \(2\) more.
Now, let's test how it works through example.
Example:
Estimate the sum of \(14.246\) and \(9.832\).
Add whole numbers only: \(14 + 9 = 23\)
Now, add \(2\) more with whole numbers: \(14 + 9 + 2 = 25\)
Let's add the actual decimals: \(14.246 + 9.832 = 24.078\)
Here, the sum will be more than \(23\) and less than \(25\).
Therefore, the actual sum will always land between the sum of the whole parts, and the whole parts plus \(2\).