Addition Facts Glass Orb

How to Play Cistern Pair

1. 1

   Read the Sum

   The plaque above the wall shows a target such as 10. You need two orbs whose numbers add to that target.

2. 2

   Tap Two Orbs

   Tap the first addend, then the second. A match glows and drops into the well. A miss is not that pair.

3. 3

   Watch the Wall

   New glass keeps sliding down the channels. Clear pairs before the wall fills to the top.

4. 4

   Fill the Cistern

   Twelve pairs win. Three overflows end the run. Remaining lives add a bonus on a win.

Key Features

• Read the Well

  A stone plaque names the sum. On Easy it stays 10. Later rounds move through 10–20, then 14–24.

• Pair the Glass

  Orbs fall down five wet channels. Tap one, then its partner. Only the pair that adds to the plaque is taken.

• Streak and Overflow

  Hits stack a streak bonus. A wrong pair clears the streak. If every channel fills, the wall overflows and you lose a life.

• Twelve Pairs

  Twelve good pairs fill the cistern and win. Three overflows end the run. Best scores save per difficulty.

What is Cistern Pair?

Cistern Pair is an addition pairing game. Numbered glass orbs slide down a wet limestone wall in a moonlit courtyard. A plaque names a sum. The player taps two orbs that add to that sum. Matches fall into a stone cistern. The goal is twelve pairs before three overflows.

Why Play Cistern Pair?

• 1

  Facts Under Motion

  Orbs keep falling, so students hunt 3 + 7 while the wall fills—not on a static worksheet.

• 2

  Two Addends, One Place

  The answer is a pair on the wall, not a button under a prompt. You tap the glass.

• 3

  Near-Miss Numbers

  A 4 and an 8 sit next to a needed 6 when the sum is 10, so students add, not guess by look.

• 4

  Grows With the Sum

  Easy stays on 10. Medium moves through 10–20. Hard uses 14–24 and a faster fall.

Frequently Asked Questions