Using dots (maximum of 5 in a row) students will quickly learn to recognise up to 25, without counting. Start by showing just the first 5 slides in order, then in random order. Students should be encouraged to say how many there are without counting. Once the first 5 slides are mastered, slowly introduce the next 5. Done regularly, students will be learning many incidental addition and subtraction facts, they will be consolidating counting by 5s and consolidating bonds of 10 and 20.