Multiplying Decimal Numbers
Multiplying decimal numbers follows a two-step process in Grade 6 Saxon Math Course 1: multiply as if the numbers are whole integers, then place the decimal point by counting the total number of decimal places in both factors. For 2.3 × 1.4: multiply 23 × 14 = 322; the factors have 1 + 1 = 2 decimal places total, so the answer is 3.22. This method avoids aligning decimal points (unlike addition) and correctly handles all decimal multiplication without converting to fractions.
Key Concepts
New Concept To multiply decimal numbers, first multiply as if they were whole numbers. Then, count the total decimal places in the factors to place the decimal.
When we multiply decimal numbers, the product has the same number of decimal places as there are in all of the factors combined. What’s next This card introduces the core rule. Next, you'll apply it through worked examples, including squaring decimals and solving real world word problems.
Common Questions
How do you multiply decimal numbers?
Multiply ignoring decimal points, then count the total decimal places in both factors and place the decimal that many places from the right in the product.
Calculate 2.3 × 1.4.
23 × 14 = 322. Total decimal places: 1 + 1 = 2. Answer: 3.22.
Calculate 0.5 × 0.6.
5 × 6 = 30. Decimal places: 1 + 1 = 2. Answer: 0.30 = 0.3.
Calculate 3.14 × 2.5.
314 × 25 = 7850. Decimal places: 2 + 1 = 3. Answer: 7.850 = 7.85.
Why don't you align decimal points when multiplying?
Decimal alignment is needed for addition/subtraction to keep place values consistent. Multiplication works differently — the total decimal places rule handles placement automatically.