Christmas Carol Cryptograms

Apply a printed number-to-letter key accurately across a whole phrase, letter by letter

Read back a decoded phrase and recognise it as a line from a familiar song

Use partly decoded words to predict the letters still missing rather than working every blank blind

The phrases differ sharply in length, so hand out puzzle 11 ("All I want for Christmas is you") to a student who needs a quick win and puzzle 13 or 19 to one who wants a longer sit

Five of the twenty decode to religious carols - Away in a Manger, Silent Night, Joy to the World, O Come All Ye Faithful and Hark! The Herald Angels Sing - which is worth knowing before the set is handed out whole in a mixed-faith classroom

The directions repeat identically on every page, so once a class has done one puzzle the rest can go out as independent work without re-teaching

Symbol-to-letter decoding - students read the number under each blank, find it in the A-to-Z key at the top of the page, and write the letter it stands for.

Sustained accuracy over a long task - the longest phrases run to fourteen words, so the same lookup has to be performed correctly dozens of times before the line resolves.

Prediction from partial information - once several letters are placed, a familiar lyric can often be completed by recognition, which rewards reading the emerging phrase rather than decoding blindly.