Week 17WednesdayMeasuring Twice: Inches and Centimeters
1Warm-up: Mental Math

2-min Fluency Warm-up — Solve in your head.

16 − 9 =

7 + 7 =

11 − 6 =

8 + 5 =

2Measure Twice: Two Units

Measure each line twice: once in inches, once in centimeters.

A.

Inches:    Centimeters:

B.

Inches:    Centimeters:

C.

Inches:    Centimeters:

3Number Talk: Why Different Numbers?

Number Talk — Explain WITHOUT measuring anything new.

When you measured line B, you got a bigger number in centimeters than in inches. But the line did not change! Why is the cm number bigger?

My thinking:

Hint: think about which unit is smaller.

4How Much Longer?

How much longer is the first object? Subtract to find out.

A rope is 45 cm long, and a stick is 28 cm long.

45 − 28 = cm longer

A table is 60 inches long, and a chair is 34 inches long.

60 − 34 = inches longer

A snake is 52 cm long, and a lizard is 19 cm long.

52 − 19 = cm longer

A slide is 96 inches long, and a bench is 48 inches long.

96 − 48 = inches longer

5Challenge: Create Your Own

Create Your Own

Draw a line below that you think is exactly 4 inches long — no ruler while you draw! Then measure it. How close were you?

My line measured: inches

How far off was I?