Skip to lesson

Math · Grade 6 Math

Chapter 1: Ratios

Tape Diagrams and Ratio Problems

Drawing the parts before you count them.

Lesson
4
Time
About 18 minutes
0 of 22 done
Part 1 of 7Let's Learn

Step 1: Let's Learn

Read it, or press Listen and follow the words.

Try it first

Maya and Dev share stickers. For every 1 sticker Maya gets, Dev gets 2. Maya gets 7 stickers. How many stickers does Dev get?

stickers

Stuck is fine. Let’s Learn shows the way next. Got it first time? You can jump ahead to Watch an Example.

Watch the idea first — 57 seconds. Then read on, and try it yourself in the next step.

Share 30 sweets between two children in the ratio 2 : 3.

Count the parts

The bar has 2 parts for one child and 3 for the other, so 5 parts in all.

Find one part

5 parts make 30, so one part is 30 ÷ 5 = 6.

Then build each share

One child gets 2 parts, so 12. The other gets 3 parts, so 18. Together that is 30.

Step 2: Try It Yourself

Tap and try it out.

Two bars in the given ratio. Their total is shown below.
First share
Second share

18 is 6 more than 12.

Step 3: In Real Life

Splitting a prize

Two friends split 90 dollars in the ratio 2 to 1. Draw 3 equal bars. Each bar is 30. 60 and 30. The picture does the dividing.

Step 4: Watch an Example

One step at a time.

Watch Ana Share $56

Ana shares $56 between two clubs in the ratio 3 : 4.

  1. Step 1

    Ana draws the bar first. The first club takes 3 boxes and the second takes 4, and every box is the same size.

    first club: ?second club: ?total: $56

Watch Leo Share $63

Leo shares $63 between two teams in the ratio 5 : 4. He starts it, and you finish it.

  1. Step 1

    Leo reads the ratio. One team takes 5 boxes of the bar and the other takes 4.

Watch Priya Work Backwards

Priya and Noor share the cost of a tent in the ratio 3 : 5. Noor pays $45. The total is what nobody has yet.

  1. Step 1

    The bar is drawn the same way as before. Priya holds 3 boxes and Noor holds 5, but this time the number given sits on one share instead of under the whole bar.

    Priya: ?Noor: $45tent: ?

Step 5: Your Turn

Practice makes it stick.

The Car Wash

Problem 1 of 17

Maya and Dev wash cars and make $84. They share it in the ratio 3 : 4. How many dollars does Maya get?

Maya: ?Devtotal: $84
dollars

The Gift

Problem 2 of 17

Ravi and Ana buy a gift together and split the cost in the ratio 2 : 5. Ana pays $35. How many dollars does the gift cost in all?

Ravi: ?Ana: $35gift: ?
dollars

Count the Parts

Join the two ratio numbers to count the parts. Divide the total by that. Then build the share you were asked for.

Problem 3 of 17

Share 20 marbles in the ratio 1 : 4. What is the smaller share?

marbles

Problem 4 of 17

Share 35 stickers in the ratio 2 : 5. What is the larger share?

stickers

Problem 5 of 17

Share 50 beads in the ratio 3 : 7. What is one part worth?

beads

Problem 6 of 17

Share 27 cards in the ratio 2 : 7. What is the smaller share?

cards

Problem 7 of 17

Share 55 shells in the ratio 5 : 6. What is the larger share?

shells

Whose Step?

One line in each page is a slip. Find it, then fix it.

Problem 8 of 17

Dev was asked to share $40 in the ratio 3 : 5 and give the larger share. One line is a slip. Which?

Dev's answer for: share $40 in the ratio 3 : 5, larger share

  1. 13 + 5 = 8 parts
  2. 2$40 ÷ 8 = $5 in one part
  3. Answerlarger share = 3 × $5 = $15

Problem 9 of 17

What should the larger share be, in dollars?

dollars

Problem 10 of 17

Noor was asked to share 45 counters in the ratio 4 : 5 and give the smaller share. One line is a slip. Which?

Noor's answer for: share 45 counters in the ratio 4 : 5, smaller share

  1. 14 + 5 = 9 parts
  2. 245 ÷ 2 = 22.5 in one part
  3. Answersmaller share = 4 × 22.5 = 90

Problem 11 of 17

What should the smaller share be?

counters

Problem 12 of 17

Ana and Sam split money in the ratio 2 : 3. Sam's share is $18, and Sam was asked for the total. One line is a slip. Which?

Sam's answer for: Ana : Sam = 2 : 3, Sam's share is $18, find the total

  1. 12 + 3 = 5 parts
  2. 2$18 ÷ 3 = $6 in one part
  3. Answertotal = 3 × $6 = $18

Problem 13 of 17

What should the total be, in dollars?

dollars

Pick the Move

Decide the first move before you make it. What you were given decides it.

Problem 14 of 17

A prize of $60 is shared in the ratio 1 : 5. What is the first move?

Problem 15 of 17

Two shares are in the ratio 3 : 7. The smaller share is $21, and the total is wanted. What is the first move?

Same Share?

Decide what is true of the bar. Some of these you can settle without finishing the arithmetic.

Problem 16 of 17

24 is shared in the ratio 1 : 2. Select every statement that is true.

Problem 17 of 17

Leo shares $30 in the ratio 1 : 2. Maya shares $30 in the ratio 2 : 4. Select every statement that is true.

Step 6: Quick Check

Show what you know.

Question 1 of 2

Share 48 in the ratio 1 : 3. What is the larger share?

Question 2 of 2

To share a total in a ratio, what do you find first?

Ready for more?Optional. Past the lesson, for anyone who wants it.

Stretch 1 of 2

Two friends share $60. The first gets twice as much as the second. How many dollars does the first get?

dollars

Stretch 2 of 2

A prize of $48 is shared between three friends in the ratio 1 : 2 : 3. How many dollars does the friend with the largest share get?

dollars

What You Learned

  • Draw the ratio as parts of a bar.
  • Divide the total by the number of parts to find one part.
  • Then build each share from the parts it has.
For the grown-up

The misconception this lesson targets is that the two ratio numbers are the shares. Asked to share 30 in the ratio 2 : 3, a child holding it answers "2 and 3", and nothing about the wording corrects them. The tape diagram is the cure, because it makes the numbers count boxes rather than candy.

The first slip is dividing by 2, the number of people, instead of by the number of parts. It is the most common wrong first line on this page, and it always produces a share bigger than the total.

The second slip appears when a share is given instead of the total, and the child divides by the whole bar rather than by the boxes that share covers. Asking "how many boxes does that number cover?" out loud catches both.

What a tape diagram shows — Draw one box for each part of the ratio: 3 boxes for red and 2 for blue. Every box is the same size, whatever that size turns out to be. The picture holds the relationship steady while you work out what one box is worth.

Find the value of one box — If a 3 : 2 mix makes 40 liters altogether, there are 5 boxes and 40 ÷ 5 = 8 liters per box. So red is 3 × 8 = 24 and blue is 2 × 8 = 16. Almost every ratio problem reduces to finding what one box is worth.

When the difference is given — If there are 12 more red than blue in a 3 : 2 mix, the difference is 1 box, so a box is 12. Red is 36 and blue is 24. The diagram tells you which quantity corresponds to the number you were given, which is what makes these problems tractable.

Check against the original ratio — Once you have both amounts, reduce them: 36 : 24 reduces to 3 : 2. If it does not match the ratio you were given, something went wrong. This check is quick and it verifies the answer rather than the arithmetic.

Draw the parts as boxes — Red to blue is 3 : 2, and there are 30 counters. Draw 3 boxes for red, 2 for blue. Five boxes in all. 30 ÷ 5 = 6 in each box. Red: 3 × 6 = 18. Blue: 2 × 6 = 12. Check: 18 + 12 = 30.