Round Sums and Differences
Estimate Express
Pilot a mail rocket by estimating sums and differences. Round each number to the nearest hundred, move a landing beacon on the number line, and launch. Complete eight deliveries with worked rounding feedback.
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How to play Estimate Express
- 1
Round first
Round each number in the delivery calculation to the nearest 100, then add or subtract.
- 2
Move the landing beacon
Drag the beacon on the number line, or use arrow keys, to set your estimate.
- 3
Launch
Launch the rocket. Read the worked rounding feedback and complete eight deliveries. Errors allow another try.
Key Features
Move the landing beacon
Drag along a number line or use arrow keys to aim your rocket.
Round first
Practice addition and subtraction with nearest-hundred estimates and worked feedback.
Frequently Asked Questions
Do I need the exact answer?
No. Round each number first, then add or subtract the rounded numbers.
Can I play with a keyboard?
Yes. Focus the landing beacon slider and use arrow keys. Press Enter to launch or continue.
