Math skills and prerequisites
What this game practices
- Find complements to 20
- Add several adjacent numbers
- Plan placement while preserving room in a column
Explore: Number bonds & target sums · Addition · Subtraction · Spatial reasoning & planning
Before playing
- Add whole numbers from 1 to 9
- Find a missing addend in a sum to 20
- Read a stack from its newest top egg downward
Getting started
Choose PLAY. Each run begins with an uneven starter skyline.
Read the falling egg and NEXT preview.
Move with Left/Right arrows or A/D. You can also choose a column with mouse or touch, or swipe sideways.
How to play
- Look for a column whose top eggs, together with the falling value, add to 20.
- Move the falling egg before it reaches the stack. Hold Down on a keyboard, swipe down, or hold FASTER on touch to make it fall more quickly.
- After landing, the game checks a contiguous group ending at the new top egg. A group totaling exactly 20 clears.
- A successful clear keeps eggs below that group and opens more room in the column.
- If the resolved stack reaches eight eggs, its column closes permanently. Keep using the remaining open columns.
- The run ends when no open column can accept an egg. PLAY AGAIN starts a new skyline.
TRY THE REASONING
Worked example
Finish a top group with 5
- A column has 4 at the bottom, then 7 and 8 on top. The falling egg is 5.
- Calculate 7 + 8 = 15, then 20 − 15 = 5. Place the 5 in that column.
- The touching top group 7 + 8 + 5 = 20 clears, leaving the bottom 4 in place.
Use a complement to 20, and check that the chosen numbers are adjacent and include the newly landed egg.
Scoring, success and round endings
- Each clear scores 100 points per cleared egg, plus 25 for each egg beyond the first two.
- Clears on consecutive placements build CHAIN. Its point multiplier increases by 0.25 per extra consecutive clear, up to ×2. A non-clearing placement breaks the chain.
- BEST saves the highest local game score. Platform rewards count successful 20 clears separately from that point score.
Modes, settings and progression
Continuous falling run
There is one gameplay mode. Gravity gradually speeds up as more eggs are placed.
Faster control
Soft drop speeds the current egg's descent; it changes control speed rather than the target sum.
Strategies and troubleshooting
- Use NEXT to reserve a promising column for the upcoming value.
- Keep some low stacks available when no immediate 20 is possible.
- A closed column stays closed. Crossing above it is possible, but it cannot accept another egg.
Classroom and home use
Suggested activity: One partner controls the falling egg while another calls a top-group sum and its missing addend. Swap roles after several placements and explain one choice that preserved room.
Questions to discuss
- What do these top eggs total, and what makes 20?
- Which eggs would clear, and which would remain?
- How can NEXT change the best place for the current egg?
This is a teaching suggestion, not an extra mode or a promised learning outcome.
Play and progress
Guest play does not require an account. For shared arcade coin rewards, use a verified account with an active player profile. Game scores and shared coins are different; only confirmed platform awards update the shared balance. Follow each game’s guide for its own restart and resume behavior.
Play Drop 20
