Numbers to 10,000
Guess the jar, then round it
Does a bigger sample make your estimate closer to the real number?
Watch first
Watch how ones build into tens, hundreds, thousands and beyond.
What you need
Tick each one as you find it — 0 of 4 ready.
Stay safe: Use dry food or buttons, and keep small items away from younger children and pets.
Plan the fair test
- Change: Whether you guess or sample a cupful first
- Measure: How far your number is from the true total
- Keep the same: Same jar, same contents, same counting method at the end
Objectives this evidences
- Round any number to the nearest 10, 100 or 1000
- Estimate and use inverse operations to check answers to a calculation
Do it, one step at a time
Step 1 of 5
- Step 1. Fill the jar and ask three people to guess how many are inside. Write every guess down.
- Step 2. Count one small cupful exactly, then count how many cupfuls fill the jar. Multiply to get your estimate.
- Step 3. Round your estimate to the nearest 10 and then the nearest 100.
- Step 4. Now count the whole jar for real, in tens, to find the true number.
- Step 5. Work out how far each guess and each estimate was from the truth.
What should happen
The sampled estimate beats the guesses every time, and rounding makes it easy to say out loud.
Think about: Rounding lost some accuracy. When is 'about 400' more useful than '387'?
Write up your result
A sentence or two is enough to save it.
The lessons behind this practical
Each one opens with the same short film, and the film has a written transcript underneath if reading is easier than watching.
Now the quiz for this topic
Questions come from the lessons behind this practical, so nothing is asked that has not been taught.
Quiz
Numbers to 10,000 quiz
12 questions from the lessons in this stage. No timer, and you can try again as many times as you like.