Review the key concepts, formulae, and examples before starting your quiz.
🔑Concepts
Definition of Decimals: A decimal number is a way of expressing fractions using a decimal point to separate the whole number part from the fractional part. Imagine a single whole unit (like a square) being divided into 10 or 100 equal pieces; these pieces represent the decimal parts.
The Decimal Point: This is a small dot placed between the ones place and the tenths place. It acts as a separator. For example, in the number , the dot tells us that is the whole part and is the part that is less than one.
Tenths Place (): This is the first position to the right of the decimal point. If you visualize a long rectangle divided into equal vertical bars, one bar represents tenth or . Ten tenths make one whole.
Hundredths Place (): This is the second position to the right of the decimal point. If you visualize a large square grid divided into small squares (like a graph), one tiny square represents hundredth or . It takes hundredths to make tenth.
Thousandths Place (): This is the third position to the right of the decimal point. Visually, if you take one of the tiny hundredth squares and divide it further into thin strips, each strip is thousandth or .
Place Value Relationship: As you move from left to right in a decimal number, the value of each place becomes times smaller. Conversely, moving from right to left, each place is times larger. For example, is times larger than .
Expanded Form: Writing a decimal as the sum of the values of its individual digits. For example, the number can be visualized as whole blocks, tenth-strips, and hundredth-squares, written as .
Equivalent Decimals: Adding zeros to the extreme right of a decimal number does not change its value. For example, , , and all represent the same amount (four tenths). Visually, tenths strips occupy the same area as hundredths squares.
📐Formulae
💡Examples
Problem 1:
Find the place value and the value of the underlined digit in .
Solution:
Step 1: Identify the position of the digit . It is the second digit to the right of the decimal point. Step 2: The second position to the right of the decimal point is the 'Hundredths' place. Step 3: Calculate the value: .
Explanation:
We use the decimal place value chart to determine that the digits after the decimal point represent tenths, hundredths, and thousandths respectively.
Problem 2:
Write the decimal number for the following expanded form: .
Solution:
Step 1: Add the whole numbers: . Step 2: Identify the tenths digit: . Step 3: Identify the hundredths digit: There is no term with , so the hundredths digit is . Step 4: Identify the thousandths digit: . Step 5: Combine them: .
Explanation:
When a specific place value (like hundredths) is missing in the expanded form, we must use zero as a placeholder in the decimal number.