Review the key concepts, formulae, and examples before starting your quiz.
🔑Concepts
Place Value Alignment: In 4-digit addition, numbers are composed of Thousands (), Hundreds (), Tens (), and Ones (). Imagine a table with four vertical columns; each digit must sit perfectly inside its designated column so that ones are under ones, tens under tens, and so on.
The Right-to-Left Rule: Always begin the addition process from the rightmost column (the Ones column). Visualize an arrow starting at the Ones and pointing leftwards through Tens, Hundreds, and finally Thousands.
Column-by-Column Addition: You add the digits in each column independently. For example, if the Thousands column has a and a , you simply add them to get . In this specific topic, the sum of digits in any column will never exceed .
Addends and the Sum: The two or more numbers being added together are called 'Addends'. The final answer you calculate is called the 'Sum'. Visually, you can think of the sum as the total value shown at the bottom of the addition stack.
Zero Property in Addition: When one of the digits in a column is , the sum for that column is equal to the other digit. For instance, if the Tens column has and , the resulting digit in the sum's Tens place is .
No-Carrying Concept: This type of addition is known as 'Simple Addition' because no column produces a value greater than . This means you do not need to pass or 'carry' any value over to the next column on the left.
📐Formulae
💡Examples
Problem 1:
Add and .
Solution:
\begin{array}{r@{\quad}cccc} & Th & H & T & O \\ & 3 & 2 & 5 & 4 \\ + & 4 & 6 & 1 & 2 \\ \hline & 7 & 8 & 6 & 6 \\ \hline \end{array}
- Add the Ones:
- Add the Tens:
- Add the Hundreds:
- Add the Thousands:
Explanation:
The numbers are arranged in columns by place value. We start from the right (Ones) and work our way to the left (Thousands). Since no individual column sum is greater than , we simply write the total of each column directly below the line.
Problem 2:
Find the sum of and .
Solution:
\begin{array}{r@{\quad}cccc} & Th & H & T & O \\ & 5 & 0 & 8 & 3 \\ + & 2 & 9 & 1 & 4 \\ \hline & 7 & 9 & 9 & 7 \\ \hline \end{array}
- Ones:
- Tens:
- Hundreds:
- Thousands:
Explanation:
Aligning the digits and in their respective place value columns allows us to add each set of digits. In the hundreds column, adding to results in , following the identity property of addition.