Year 9 maths lesson · Fractions

Mixed Numbers and Improper Fractions

Convert between mixed numbers and improper fractions in both directions. Improper-to-mixed uses division with remainders; mixed-to-improper uses multiply-then-add.

  • About 4–7 minutes
  • 5 quick questions as you go
  • Then about 5 minutes of practice

Worked examples

Convert 57/5 to a mixed number

  1. 57 ÷ 5 = 11 remainder 2
  2. The quotient becomes the whole number, the remainder becomes the numerator
  3. 57/5 = 11 2/5

Convert 50/7 to a mixed number

  1. 50 ÷ 7 = 7 remainder 1
  2. 50/7 = 7 1/7

Convert 10 2/5 to an improper fraction

  1. Misconception: student tries 10 + 2 = 12, giving 12/5 (wrong)
  2. Correct: multiply whole × denominator — 10 × 5 = 50
  3. Add the numerator: 50 + 2 = 52
  4. 10 2/5 = 52/5

Convert 6 3/8 to an improper fraction

  1. 6 × 8 = 48
  2. 48 + 3 = 51
  3. 6 3/8 = 51/8

Before this lesson

It helps to be comfortable with:

  • Fractions
  • Division with remainders

Lesson transcript

Everything the lesson says, word for word

Student: Hey Alex, what are we working on today?

Teacher: Do you know what that number is?

Student: 57 fifths? I could draw that… circles split into 5 pieces, shade in 57 of them…

Student: That’s going to be a LOT of circles.

Teacher: Right. But think about what you’re actually doing — you’re trying to figure out how many wholes you can make from 57 fifths.

Teacher: Each whole is 5 fifths. So really you’re asking, how many 5s fit into 57?

Teacher: Let’s skip the pictures and do that a faster way.

Teacher: Did you know the fraction line means divide?

Student: I think my teacher said that once…

Teacher: It’s really important. Fractions and division are the same thing. It comes up everywhere — algebra, converting fractions to decimals on your calculator… loads of things. But today, let’s just use it to convert improper fractions.

Teacher: So 57 over 5 is the same as 57 divided by 5. How many 5s go into 57?

Student: Well, I know 11 fives are 55… so that’s 11 times with 2 left over.

Teacher: So 57 divided by 5 is 11 remainder 2. So 11 whole times and the 2 still needs dividing by 5 — so the answer is 11 and 2 fifths.

Student: Oh I see! The remainder just becomes the numerator.

Teacher: Try this one. What’s 50 over 7?

Student: 50 divided by 7… well I know 7 sevens are 49, so that’s 7 times with 1 left over. So it’s 7 and 1 seventh!

Teacher: Perfect.

Teacher: Now what about the other way? Can you turn 10 and 2 fifths into an improper fraction?

Student: So I just put the numbers together… 10 plus 2 is 12… so 12 over 5?

Teacher: Not quite. Think about what those 10 wholes actually mean. Each whole was made up of 5 fifths. So 10 wholes is 10 lots of 5 — that’s 50 fifths. Then add the 2 that were left over.

Student: Oh! 50 fifths plus 2 makes 52 fifths. That makes way more sense.

Teacher: Try this one. Turn 6 and 3 eighths into an improper fraction.

Student: OK so… the whole number times the denominator… 6 times 8 is 48…

Student: Then add the numerator… 48 plus 3 is 51. So it’s 51 over 8!

Teacher: Exactly right. Multiply the whole number by the denominator, then add the numerator. That’s all there is to it.

Teacher: Right, try these questions then.

More Fractions lessons

Next lesson: Adding and Subtracting Fractions →All Year 9 Number lessonsAll lessons