Conjecture: an opinion or conclusion formed on the basis of incomplete information. synonyms: speculation, guesswork, surmise, fancy, presumption, assumption, theory, postulation, supposition. We can use conjectures in math and English by coming up with theories or ideas about how things work. First the teacher provides us with a task or a question. Students solve the problem or share their ideas and then try to come up with an explanation or theory. English Conjecture: can we group plural words together in groups and explain the rules for turning singular words into a plurals? We are learning plural rules - as a whole class, we have made a conjecture already about words ending in y. Initially our conjecture was that all words ending in a y needed to be changed when adding an s. We had to change the 'y' into an 'ie'. Then Ms Leanne gave us some words ending in y and we tried to turn them into plurals to test our theory. We decided our conjecture was