Stay busy with our brainteasers

In addition to our weekly puzzle we post on Twitter, we've got more to get your teeth into - some family-friendly and others a little more taxing!
If you get stuck, why not get others in your household involved and see if you can tackle them together.
Still stuck? We’ve also got some helpful puzzle-solving tips for you. The solutions will be hidden below each puzzle.
And if that’s not enough for you, you can always search the hashtag #GCHQPuzzle on Twitter for more puzzles and challenges or dig back through our puzzle archives.
Happy puzzling!
Week Twelve - Head-scratcher

Find the word:
Madison, Saturn, Do, Nitrogen, Exodus

INDEX. Each word is the nth in a sequence. US Presidents, planets in the solar system, the tonic sol-fa scale, periodic table, books of the bible. By taking the nth letter in the word you can spell out INDEX.
Week Twelve - Family-friendly

Which word or phrase is the odd one out?
Catwoman, Deus Ex Machina, Parishioner, Pyromania, Scuba

Parishioner. It starts with a capital city. The others end in a country
Week Eleven - Head-scratcher

The following list consists of pairs of words which are in some sense opposites - and an odd word out. What are the pairs and which is the odd word out?
Boxing, down, ergo, grog, hiss, home, mail, ogre, oppo, rattle, reform, silent, sites, tilt, tomtom, wash, up

Home. The pairings are: Boxing/silent (precede day and night), Down/Up, Ergo/Ogre (reversals of each other), Hiss/TomTom (all dots and all dashes in Morse code), Mail/Wash (can be prefixed with Black and White), Oppo/Sites, Rattle/reform (anagrams of Latter and Former)
Week Eleven - Family-friendly

What comes next in the sequence?
7, 8, 5, 5, 3, 4, 4, ?

Six. The sequence is the number of letters in the names of months. August has six letters.
Week Ten - Head-scratcher

In English it's (910, 911, 912). In German it's (511, 512, 513). What is it in French?

(37, 38, 39). These are the smallest triples of consecutive numbers in each language where the last letter of a number is the first letter of its successor
Week Ten - Family-friendly

What completes the list?
Sore, Keel, Cosh Mark

The list. The words are anagrams of rose, leek, shamrock and thistle which are symbols of parts of the UK. THE LIST is an anagram of thistle.
Week Nine - Head-scratcher

Which mathematician is hiding in this sequence?
8, 34, 1, 610, 377, 1, 2, 2, 34

Fibonacci. The letters are replaced by the Fibonacci sequence.
Week Nine - Family-friendly

When we quizzed a group of musical artists about their favourite Pokemon, there were no surprises. Danniel Merriweather said Charizard. Eiffel 65 chose Blastoise. Coldplay said Pikachu. Spandau Ballet chose Ho-Oh. Echo and the Bunnymen said Lugia and New Order said Suicune. But what answer did the Kaiser Chiefs give?

Groudon. The band had songs called Red, Blue, Yellow, Gold, Silver and Crystal. These are also names of Pokemon games and the corresponding characters featured on each box. The Kaiser Chiefs have a song called Ruby, of which Groudon is the game's mascot.
Week Eight - Head-scratcher

What comes next?
M, N. A, I, W. C, O; ?

K, S, T V. The sequence is that of letters that start the names of multiple states of the USA. M and N start 8 names each. A, I and W start 4 names each. C and O start 3 names each and L, S, T and V start 2 names each.
Week Eight - Family-friendly

What property do these words share?
Bad, ball, dan, mass, pat, tan

The A can be replaced by any other vowel and still form a legitimate English word.
Week Seven - Head-scratcher

Vinegar + carbolic acid + carbon dioxide - aspirin = ?

Water, Chemical formulae: C2H4O2 + C6H6O + CO2 - C9H8O4 = H2O
Week Seven - Family-friendly

Which 6-letter girls names begins this list?
?, had, inland, ran, man, pain

Olivia. Each word can become a country by adding a letter at the beginning and these letters are in alphabetical order. B-Olivia, C-Had, F-Inland, I-Ran, O-Man, S-Pain
Week Six - Head-scratcher

I have written a word. I cross out the first letter and add a letter to the end to make a new word. Then I do this a second time, and a third. For example I could have written the words SHOP, HOPE, OPEN, PEND. However, with the words I've actually written, the first pair sounds the same, as do the last pair. What are the four words?

WRY - RYE - YEW - EWE
Week Six - Family-friendly

If R + B = P and R + Y = O then B + Y = what?

G. Red mixed with blue makes purple; red mixed with yellow makes orange; blue mixed with yellow makes green.
Week Five - Head-scratcher

Explain the following. Falkun, home de guerra, kick, lavoro, mood, mosca, raccordement, schafer, stobhach, tre, zevk

Maltese falcon, Portugese man o'war, Swedish chef, Italian job, Dutch courage, Spanish fly, French connection, German shepherd, Irish stew, Norwegian wood, Turkish delight
Week Five - Family-friendly

Complete the sequence. C, F, T, ?, Y, H, N, J, I, ?

6, 9. The characters are a diagonal pattern on a computer keyboard
Week Four - Head-scratcher

What animal completes the sequence?
IDYHHTS, DTDWEOS, EHAORRC, ?
Need a hint?
Try not to think outside the box!

Chicken. Writing the sequence in a grid and adding this word, the phrase 'Why did the chicken cross the road' is spelled out.
Week Four - Family-friendly

If C = SB, CP = SP, E = GP and MU = OT, what does L =?

A. The pairs are Premier League clubs and their grounds. Chelsea = Stamford Bridge, Crystal Palace = Selhurst Park, Everton = Goodison Park, Manchester United = Old Trafford, Liverpool = Anfield
Week Three - Head-scratcher

Pair up these words.
Ail, any, car, cur, end, fen, key, old, pan, row, rut, sew, spy, vat

Anagrams of European countries. Ail + vat = Latvia, Any + row = Norway, Car + fen = France, Cur + spy = Cyprus, End + sew = Sweden, Key + rut = Turkey, Old + pan = Poland
Week Three - Family-friendly puzzle

What four words come before all of the following?
PS, COS, POA, GOF, OOTP ,H-BP, DH

Harry Potter and the. The letters are the initial letters of the ends of Harry Potter book titles
Week Two - Head-scratcher

Which wins?
Match 1 - Swing v Essay. Match 2 - Cuts v Mail. Match 3 Deed v Hold. Match 4 - Music v Snips. Match 5 - Rag v Tor. Match 6 - Shears v Thesis. Match 7 - Mirror v Cobble. Match 8 - Zigzags v Disturb. The winner of match 1 faces the winner of match 2, etc.

Music. Each bout is a game of Rock, Paper, Scissors represented by synonyms. Essay defeats Swing, Cuts defeats mail, hold defeats deed, music defeats snips, rag defeats tor, shears defeats thesis, mirror defeats cobble and disturb defeats zigzags. In the next round Cuts defeats essay, music defeats hold, shears defeats rag and mirror defeats disturb. In the semi finals music defeats cuts and shears defeats mirror. Music defeats shears in the final
Week Two - Family-friendly puzzle

Fill in the gaps. _ _ _ L, I, _. _ _ _ L, A. _ _ _ L, O. _ _ _ _, L, E space _ _ _ _.

Violin, Viola, Cello, Double Bass
Week One - Head-scratcher

In the league table every team has played each other once. It is ordered in the usual way - 3 points for a win and 1 for a draw with goal difference and goals for used as tiebreakers. Complete the table.
First place - Wanderers. Five points, three goals for, blank goals again and blank goal difference.
Second place - United. Blank points, blank goals for, six goals against and two goal difference.
Third place - City. Four points, blank goals for, blank goals against and blank goal difference.
Fourth place - Rovers. Three points, blank goals for, three goals against and blank goal difference.
United vs Rovers finished 1-3. Wanderers v City finished blank-0. City v Rovers finished blank-blank. Wanderers v United finished blank-2. City v United finished blank-blank. Rovers v Wanderers finished blank-blank.

Week One - Family-friendly puzzle

Replace the the asterisks with animals to make words.
Appr*imate, mead*ark, bil*aire, af*oon, bene*nt, b*zebub, ver*im, si*ure, *orker, mi*ave, ex*ble, cont*e

Approximate, Meadowlark, Billionaire, afternoon, benevolent, Beelzebub, verbatim, signature, coworker, microwave, expandable, contravene
Top Tips for Brainteasers
- Really read the brainteaser and think about it from all angles. Is there a code hidden within the characters? An anagram perhaps?
- If you're stuck ask a friend or family member - it's not cheating! People come at problems from different perspectives. A solution can often be found by using a mix of minds.
- If you're having no luck, take a break. Inspiration can hit when you're not focused on the problem.


