Return to decimals to learn multiplication and division, and discover what happens when fractions convert to repeating decimals.
To multiply decimals, multiply as whole numbers first, then count the total decimal places in both numbers to place the decimal point in the answer. To divide by a decimal, shift both decimal points to make the divisor a whole number.
Find: 2.5 × 3.4
25 × 34 = 850, with 2 total decimal places → 8.50
Find: 7.2 ÷ 0.8
Shift both decimals: 72 ÷ 8 = 9
Not every fraction converts to a decimal that ends. Some fractions produce a repeating decimal, where a digit or group of digits repeats forever, shown with a bar over the repeating part.
Convert 1/3 to a decimal.
0.333... (written as 0.3̄, since 3 repeats forever)
Convert 1/6 to a decimal.
0.1666... (written as 0.16̄, since 6 repeats forever)
1. Find: 4.3 × 2.6
2. Find: 9.6 ÷ 1.2
3. Convert 2/3 to a decimal.
4. Convert 5/9 to a decimal.
5. Can the product of two decimals be a whole number? Give an example.