Students have to identify and total key words from the lesson using scrabble blocks. To enhance this you could give students a point score they have to get to with three or more words, or be selective of the letters placed on the board. This is then getting the students to think about which words to choose and practising their basic addition skills.
To extend this activity you could get students to find a key word, total the tiles and then complete a series of operations. (E.g. double, add 4 ...) You could also ask the students to find averages of the tiles.