What this lesson shows
A jar of marbles: count one group of 10, see that the jar holds about 5 groups like it, and estimate 50. Counting finds 47, close to the estimate.
The worked example
The lesson works this one step by step: a jar of 47 marbles. Then your kid tries one like it on paper.
The steps
- Find one group of 10
- How many groups fill the jar?
- Estimate by tens
- Count to check: is it close?
Helping at home
Have your kid circle one group of 10 marbles, then guess how many groups like it fill the jar, and say the estimate by tens. Then count by tens to check. Ask: is the count close to the estimate? Would 10 or 200 make sense?
If your kid gets stuck
Circle a group of 10 first. How many groups like it fill the jar?
Watch it with Lux
With Lux, this lesson is a narrated video and a printed page your kid works on. Then Lux helps with the same math on their own worksheet, one question at a time.
More in this unit
- Counting on and back to 120
- The end of a row
- Skip counting by 2s and 5s
- Tens and ones
- Fifteen is not 51
- Expanded form counts tens
- Many ways to make a number
- Extra ones make a ten
- One more, ten more
- Ten more changes the tens
- Greater than, less than
- Numbers on a number line
- The tens decide first
- Growing patterns
- About, nearly, and benchmarks