Idea 10of 23Builds onThe price for 100 gCompare the price for one
Change kilograms to grams first
How do you compare a pack in kilograms with one in grams?
Today you'll discover
- how many grams are in a kilogram
- why units must match
- how to compare fairly
Think first2 kg for $7.00, or 500 g for $2.00
Rice: 2 kg for $7.00, or 500 g for $2.00. Which costs less per 100 g?
Decide first, then press Next. Put both packs in grams before you divide.
A 2 kg bag of rice for $7.00 and a smaller 500 g bag for $2.00. Under the tags, the lines 2 kg = 2000 g = 20 × 100 g and 500 g = 5 × 100 g, with bars cut into 20 and 5 parts. Then $7.00 ÷ 20 = $0.35 and $2.00 ÷ 5 = $0.40. Along the bottom, the $0.35 bar is ticked. The last step asks about 1.5 kg of flour for $4.80 or 800 g for $2.40.
See the whole ideathe big idea and the key word, in one place
The big idea
Change both to the same unit first: 1 kg = 1000 g. Then compare.
Kilograms to grams
Multiply by 1000: 1 kg = 1000 g, 2 kg = 2000 g, 1.5 kg = 1500 g.
- 1 kg1000 g
- 1.5 kg1500 g
- 2 kg2000 g
Easy to get wrongNever compare 2 and 500 as they are. The units differ, so change one first.
Key word
- kilogram
- a unit of mass equal to 1000 grams, written kg
Ready to use it?
- Change kilograms to grams before comparing.
- Compare two packs in different units.