Place all decimal towers in line on your desk. If children in the back desks cannot see clearly, ask them to move closer, or gather around you.
Explain that each tower represents a unit, a whole number. Go on to say that in math, every number can be divided in smaller parts. Place the "1" and the "0.5" towers in front of the others to reinforce this point, and to show the relationship of halves.
Repeat the task by dismantling the "0.25" tower to show its connection with "1" (quarter) and "0.5" (half of half). Ask children to count the number of blocks each tower consists of to find out the fraction each represents. Demonstrate, for instance, that the "0.25" tower has four blocks, therefore each represents 1/4.
Ask children to make groups of four and distribute a set of decimal blocks to each team. If you have only one set, make a workshop and allow one group at a time to undertake tasks, while the rest of the class observes.
Instruct groups to build a tower for specific decimals, such as 0.35, 0.80, 1.33 and so forth as quickly as possible, rewarding the fastest team. Through this activity, you can determine whether students have understood the concept of decimals without the stress of quizzes or exams.
Practice operations with decimals by asking students to subtract 0.3 from one tower, or multiplying 0.25 by three. Instruct children to use the decimal towers to "simulate" the operations and find the correct answers.