Cogito
Grade 3 Math · Chapter 2 · Lesson 8
Grams and Kilograms
Reading a scale to find a mass.
10 problems · about 12 minutes · 3.MD.A.2
What this lesson teaches
The child measures and estimates masses in grams and kilograms and reads a scale.
- Mass is how heavy something is.
- Grams for light things, kilograms for heavy ones.
- One kilogram is 1,000 grams.
Warm-Up Review
From earlier lessons. Loosen up before the new work.
3 problemsReview — Time Intervals: From 7:45 to 8:10. How many minutes?
Answer 25
Why 15 + 10 = 25 minutes.
Review — Telling Time to the Minute: One mark past the 9. How many minutes past the hour?
Answer 46
Why 45 and 1 more is 46.
Review — Subtracting Within 1,000 Fluently: 905 − 348 = ?
Answer 557
Why 905 − 348 = 557.
Warm Up
Straightforward practice. Get the method working first.
3 problemsHow many grams are in one kilogram?
Answer 1000
Why 1 kg = 1,000 g.
The needle sits halfway between 400 and 500 grams. What is the mass?
Answer 450
Why It reads 450 grams.
How many grams in 2 kilograms?
Answer 2000
Why 1,000 twice.
Build It Up
The same ideas with more to keep track of.
1 problemWhich unit fits an apple?
Answer Grams.
Why An apple is light.
Stretch Yourself
Mixed problems. Work out what kind of question it is before you start.
3 problemsA parcel of 300 g and one of 250 g. What is the total mass?
Answer 550
Why 300 + 250.
Choosing a Unit: Which unit would you use to weigh a person?
Answer Kilograms.
Why People are weighed in kilograms.
How Many Grams: How many grams are in one kilogram?
Answer 1000 grams
Why 1 kg = 1,000 g.