Ship: 3.0 miles from the reef
A storm on the coast

The lighthouse is dark

A rescue ship is sailing straight toward the rocks, and the crew can’t see the danger. Only you can get the light shining again.

Your mission

The storm broke the lens, the generator, and the radio. Each room has a math puzzle that fixes one of them. Fix all three, then send a signal before the ship reaches the rocks.

1
Lens roomMatch a ratio
2
Generator roomFill a ratio table
3
Radio roomFind a unit rate
4
Signal gallerySet the signal
How it works
Hints are always freeTap the lightbulb in any room. Use as many as you like.
Practice first if you’re unsureEach room has a short practice to help you warm up. Look for the pencil in the top corner.
Collect cluesEach fixed room gives you a clue for your logbook. You’ll need them at the end.
Unlock each doorUse what you solved to open the door to the next room.
Tap the lighthouse to climb in
{{ progLabel }}{{ shipText }}
{{ s.name }}
Clues {{ jCount }}
{{ j.glyph }}{{ j.name }}
⚡ Just as you reach the top

Lightning strikes the tower

The bolt knocks out 2 of your power packs and shatters part of the lens. Then the radio crackles: the ship’s crew needs a longer rescue message.

Good news: what you found still worksThe storm changed the amounts, not the patterns. The lens still uses the same mix of blue and gold. Power packs still make flashes at the same rate. The radio still beeps at the same speed. Use what you found in each room to work out the new numbers.
New orders
{{ o.l }}{{ o.was }}{{ o.now }}
Meanwhile, out at sea… {{ tTitle }} {{ tMsg }}
{{ tLbl }}
{{ mapAlt }}
Inside the lighthouse {{ mTitle }} {{ mMsg }}
{{ mLbl }}
✓ {{ doneTitle }}{{ doneText }}Your strategy: {{ stratName }}
{{ place }}
{{ lensCountBig }} blue · gold
Generator control panelHow many flashes do 10 power packs make?
Power packs4810 Flashes612
Generator output {{ genRead }}
{{ rTitle }}{{ rQ }}
{{ m.l }}
{{ rVal }}
Your dial {{ rSum }}
  1. {{ g.name }}
    2.
Explain your signalWhy will this signal work? Finish the sentence with numbers.

My signal usespower packs, and I have. The message takesminutes, and the ship arrives inminutes. So my plan fits both my supplies and the time.
{{ d.name }}
{{ m.l }}
{{ d.valText }}
{{ gDialTitle }}{{ gQ }}
Lens pattern:
{{ toastGlyph }} {{ toastT }}{{ toastS }}
Hints
Hints are always free. Use as many as you like!
{{ h.n }}{{ h.t }}
The ship sees the beacon
Current settings Lens · {{ patShow }} Flashes · {{ flShow }} Radio · {{ duShow }}
Your logbook · {{ gRoom }}{{ gFound }}
Use this to answer the question on the dial above.
{{ l.glyph }}{{ l.room }}{{ l.clue }}{{ l.strat }}
{{ ctlHelp }}
Check the groupsHow many groups of 5 fit in the 20 spots?One group is 2 blue and 3 gold, or 5 spots.
Share your strategyHow did you solve it?Pick the way that matches your thinking.
{{ doorTitle }}
{{ doorPrompt }}
{{ fbText }} {{ fbIdle }}
  1. {{ s.name }}
    2.
Practice
Part {{ ppN }} of 3 · {{ ppName }}

A ratio compares two amounts. In the lens, it tells you how many blue lights go with how many gold lights.

Example: 1 blue for every 4 gold
1 : 4
Read it as “1 to 4.” Order matters: blue comes first, then gold.
Two groups of the same ratio
2 : 8
More lights, same ratio. Each group still has 1 blue for every 4 gold. Ratios that match like this are called equivalent ratios.
Describe it Look at this group. Finish the sentence using “for every.” There are {{ dBv }} blue lights for every {{ dGv }} gold lights.
Blue
Gold

{{ dFb }}
{{ q.n }} {{ q.text }}

{{ q.fb }}

A small signal lamp has 10 spots. It needs the ratio 1 blue : 4 gold. One group of that ratio uses 5 spots.

How many groups of 5 fit in 10 spots?

{{ pgFb }}
Now build both groups. Each one needs 1 blue and 4 gold.
Pick a color, then tap a spot:
{{ g.name }}
{{ g.count }}
Tap a spot again to empty it. Whole lamp: {{ pCount }}

{{ pfMsg }}
Part {{ ppN }} of 3 · {{ ppName }}

{{ gIntro }}

{{ x.title }}
{{ r.label }}{{ c.v }}
 {{ x.big }} {{ x.cap }}
Build it Each group is 2 power packs for every 5 flashes. Add groups to build a tape diagram until you have 6 packs.
Packs
2
Flashes
5
{{ tapeN }}{{ tapeSum }}

{{ tapeFb }}
Draw it A buoy sends 20 beeps in 4 minutes. Split the beeps into equal parts, one part for each minute.
{{ l.t }}
{{ splitN }}

{{ splitFb }}
{{ q.n }} {{ q.text }}

{{ q.fb }}

{{ gTask }}

{{ i.fb }}

{{ pfMsg }}
Explain it Finish the sentence to explain why the practice signal works. The signal works because {{ xAv }}, and {{ xBv }}. Supplies
Time

{{ xFb }}

The lighthouse is dark

A rescue ship is heading toward the rocks, and it needs a signal. Can you get the lighthouse shining again?

The storm broke three things: the lens, the generator, and the radio. Each room has a math puzzle that fixes one of them. There’s no rush, and hints are there whenever you want them.
Room 1 · Lens room

Match the colors

The storm cracked the lens. 4 gold panels made it through and are stuck in place. Your job: fill the other 16 spots so the whole lens has 2 blue lights for every 3 gold lights.

The ratio2 blue : 3 gold
Pick blue or gold below the lens, then tap a spot to fill it.
Tap a spot again to empty it. The brass-ringed panels can’t move. {{ lensCount }}
Each group of 5 needs2 blue : 3 gold
Your lens{{ lensYours }}
Room 2 · Generator room

Power packs and flashes

The generator runs on power packs, and 4 power packs make 6 flashes. Find the missing number to get it running again.

Want a way to start? (optional)
{{ stratText }}
Room 3 · Radio room

How fast is the radio?

The radio sent 18 beeps in 3 minutes. First, figure out how many beeps it sends each minute. Then find how long it will take to send all 42 beeps of the rescue message.
Room 4 · Signal gallery

Set the signal

One last challenge before the ship reaches the rocks.

⚡ After the storm
{{ m.n }}{{ m.l }}was {{ m.was }}

Last step: finish the sentence on the picture to explain why your signal works.

Nice work! The beacon is lit.

The rescue ship made it safely to the harbor, and you’re the reason why. You used ratios and rates, found every clue, and solved each room. Here’s what you figured out along the way.

{{ r.room }}{{ r.t }}