Cogito
Grade 3 Math · Chapter 6 · Lesson 2
Scaled Bar Graphs
When the scale counts in twos, fives, or tens.
10 problems · about 13 minutes · 3.MD.B.3
What this lesson teaches
The child reads a bar graph whose scale steps by more than one.
- A scaled bar graph steps by more than one.
- Read the numbers on the axis, not the number of marks.
- Work out what half a step is worth for bars in between.
Warm-Up Review
From earlier lessons. Loosen up before the new work.
3 problemsReview — Scaled Picture Graphs: Each picture is 5. A column has 8 pictures. How many?
Answer 40
Why The column stands for 40.
Review — Fractions of Different Wholes: Two same-size pizzas. Which is more, 3/4 or 1/2?
Answer 3/4
Why 3/4 is greater than 1/2 of the same whole.
Review — Fractions Greater Than One: How many fifths land on the 2?
Answer 10
Why 10/5 = 2.
Warm Up
Straightforward practice. Get the method working first.
3 problemsA scale of 5, bar at the seventh mark. What value?
Answer 35
Why The bar shows 35.
Why check the scale first?
Answer A mark can be worth more than one.
Why The scale tells you what each step is worth.
A scale of 5, bar at the sixth mark. What value?
Answer 30
Why 6 × 5.
Build It Up
The same ideas with more to keep track of.
1 problemA scale of 2, bar at the seventh mark. What value?
Answer 14
Why 7 × 2.
Stretch Yourself
Mixed problems. Work out what kind of question it is before you start.
3 problemsA scale of 5. Bars at 30 and 15. How many more is the first?
Answer 15
Why 30 − 15.
The Class Survey: A scale steps by 10. A bar reaches the fourth mark. What value is it?
Answer 40
Why The bar shows 40.
Halfway Up: On a scale stepping by 10, a bar sits halfway between 20 and 30. What is it?
Answer 25
Why The bar shows 25.