Add Integers on a Number Line
Integer Express
Drive a cloud railway courier to the sum of two integers. Use the number line to choose a station, then cancel positive and negative counters before delivering the remaining cargo. Complete six deliveries in this seventh-grade math game.
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How to Play Integer Express
- 1
Find the starting station
Read the first number in the equation. The train is already at that tick on the number line.
- 2
Choose a station
Use the second number to decide how far to travel. Move right for a positive number and left for a negative number. Select the station where that move ends.
- 3
Cancel and deliver
Select Cancel a pair for each +1 and −1 you can match. When no more pairs remain, select Deliver. An empty tray represents zero.
- 4
Take another route
Select Next delivery to continue. After six deliveries, select Play again to reset the score and get a new set of routes.
Key Features
Drive along a number line
The train starts on the first addend. Choose a numbered station by using the sign and size of the second addend. The trail shows the move you made.
Cancel opposite counters
Use Cancel a pair to remove one +1 and one −1. Repeat until the remaining counters all have the same sign or the tray is empty.
Check your route
If you choose a wrong station, compare your move with the second addend and try again. The train returns to its starting station.
Complete six deliveries
Deliver the remaining counters to earn points. A correct first attempt builds a streak, and Play again deals another set of routes.
What is Integer Express?
Integer Express is a seventh-grade math game that models the same integer sum on a number line and with signed counters. The first addend sets the train's starting station. The second addend tells you the direction and distance to travel. For −8 + 5, start at −8 and move five ticks to the right to reach −3. In the cargo tray, cancel five pairs from eight negative counters and five positive counters. Three negative counters remain, so the tray and the train both show −3.
Why Play Integer Express?
- 1
Connect sign and direction
A negative second addend moves the train left, even when the train is already on a negative station.
- 2
See why opposites add to zero
Every +1 and −1 pair contributes zero. Equal counts of opposite signs leave the tray empty and land the train at station 0.
- 3
Compare two representations
The signed counters left after canceling have the same value as the station where the train lands.
- 4
Practice a mix of sums
Routes include same-sign addends, opposite signs, trips across zero, and stops at zero.
Frequently Asked Questions
What happens when both addends are negative?
The train starts left of zero and travels farther left. For −4 + (−6), it moves six ticks left to −10. All ten negative counters stay in the tray.
Why can I cancel a positive and a negative counter?
Their total is +1 + (−1) = 0. Removing them together preserves the value of the cargo.
What if I choose the wrong station?
You see the attempted move, then the train returns to the starting station. Try again on the same delivery. A mistake resets the streak.
How do points work?
A completed delivery earns 100 points. Consecutive first-attempt deliveries add a streak bonus of 10 points per prior delivery in the streak. The best score is saved in this browser.
Can I use a touchscreen or keyboard?
Yes. Tap or click stations and buttons, or use Tab to focus a control and Enter or Space to select it. The sound button toggles the background music.
