83
Changing a mixed number into an improper fraction
Textbook: Part 3, lesson 83, pp. 37–39
GoalChanging a mixed number into an improper fraction: multiply the whole part by the denominator and add the numerator; writing a whole number as a fraction.
New words
mixed number · aralash kasrmultiply · ko‘paytirishadd · qo‘shishwhole number · butun son
Explanation
To write a mixed number as an improper fraction, multiply the whole part by the denominator and add the numerator. The result is the new numerator; the denominator stays the same. For example 3 2/5 = (3 × 5 + 2)/5 = 17/5. A whole number can also be written as a fraction: 5 = 15/3, because 15 : 3 = 5.
Worked examples
1 5/6 = (1 × 6 + 5)/6 = 11/6.
4 3/10 = (4 × 10 + 3)/10 = 43/10.
Class activity
“Both ways”: in pairs, one child says a mixed number and the other changes it to an improper fraction, then they do the reverse. Check the results.
Practice
1
Write 4 3/7 as an improper fraction.
31/7
2
Write 2 5/6 as an improper fraction.
17/6
3
What is the numerator when 6 1/8 is written as an improper fraction?
49
4
Cakes are cut into 8 equal pieces. On the table there are 2 whole cakes and 5 more pieces. How many pieces (eighths) are there altogether?
21
5
Write the whole number 7 as a fraction with denominator 4.
28/4