How do we measure something? As learners are beginning to grasp the idea of a consistent unit of measurement, give them this activity as a warm-up. They see an apple with a column of blocks beside it. Ask them how high the apple is, trying to get them to use the blocks as a system of measurement. Encourage marking the column to help learners see how many blocks the apple takes up. An explanation below gives a step-by-step description, and can be used or left out.