Concept 3 of 8
Weighing Scale: Grams and Kilograms
Today's big idea
A level balance proves 1 kg and 1000 g are one weight with two names.
Swapping both to grams is the only safe way to compare 950 g with 1 kg.
How it works
👀 What's going on?
A feather is light. A brick is heavy. Weight tells you how heavy something is, and we write it in grams for small things and kilograms for large ones.
💡 Here's the trick
Look at the scale above. One pan holds 1 kg, the other holds 1000 g, and the beam sits perfectly level. Level means neither side is heavier. So 1 kg and 1000 g are one weight with two names. Going from kg to g you multiply by 1000, and coming back you divide by 1000.
🪄 How to do it
- 1.Read the weight on the scale above, and note its unit.
- 2.To turn kg into g, multiply by 1000.
- 3.To turn g into kg, divide by 1000 and keep the leftover as grams.
✍️ Try it
- 1.A melon weighs 3 kg. What is that in grams?
- 2.A sack of flour weighs 6075 g. Write that weight in kg and g.
The melon is 3 × 1000 = 3000 g. The flour splits instead: 6075 g holds 6 whole kilograms, and 75 g is left over, so it is 6 kg 75 g.
⚠️ Watch out
You might be thinking 6075 g is 6 kg 750 g, since 75 and 750 look so alike. Count the digits instead of trusting your eye. The last three digits are always the grams, and here they read 075, so the answer is 6 kg 75 g.
🌟 Why this matters
Weighing is part of cooking, shopping, and packing a suitcase for a flight. An airline allows 20 kg, and a bag labelled 19500 g is under that, even though 19500 looks like the bigger number. Only the same unit tells you the truth.
Exam tip: Write every compound weight in grams first, then compare or add.
Watch me solve one
Quanta solves it
“Watch how I think through one of these — then you try.”
THE PROBLEM
“A bag weighs 3 kg 250 g. How many grams is that?”
- 1
Recall the conversion
1 kg = 1,000 g. ⚖️
- 2
Convert the kilograms
3 kg = 3 × 1,000 = 3,000 g.
- 3
Add the leftover grams
3,000 + 250 = 3,250
- 4
Total ✓
3 kg 250 g = 3,250 g
Now you try one — same steps, different story 👇
See it in action
⚡ Time to play!
Add weights to the right pan until it balances the 1.5 kg parcel.
WEIGHT · ROUND 1 OF 3
parcel
1.5 kg
your pan
0 g
Quick check
✅ VERIFICATION
A parcel weighs 2 kg 80 g. Which of these is the same weight?
⚡ Finish the activity above first to answer.
Keep going!
Up next: Reading Scales & Rulers
Big marks = whole units. Small marks = pieces.