Draw simple pictures of two different things on the blackboard in different quantities of each. You can draw stick figures of animals such as cats and dogs on the board, or bring charts containing pictures of these animals to the classroom. Ask the students to count the number of cats and dogs, and write it down on the board in the form of a ratio, such as 2:3. In another example, the number of bunnies and hamsters in ratio form might be 6:9. Let the students count as many different animals or simple items as necessary for them to grasp and understand the concept of ratio.
Divide the students into different groups and provide them with triangles and squares of different colors. Ask each group to state the number of triangles versus the number of squares, and record the numbers in ratios, such as 3:12, 9:18, 4:8 and 6:12. This simple task helps the students in better understanding the concept of ratios in class with a hands-on activity. Ask the students to simplify the ratios into their lowest form. The ratios in the above examples will reduce to 1:4, 1:2, 1: 2 and 1: 2. Make the point that three of the ratios -- 9:18, 4:8 and 6:12 -- while having different actual numbers, are equal when reduced. Thus, in the math sense, they are proportional ratios. When you distribute the different shapes, ensure that some of the groups have proportional ratios so this concept can be demonstrated.
Ask the students to identify ratios by counting the number of girls in the classroom in comparison with the number of boys. If the numbers are 14 and 17 respectively, write it down on the board as 14:17, labeling each side of the ratio with what was being counted. Ask the students to identify the number in the class with, for example, blond hair and brown hair, and write out the ratio on the board. Perhaps it is 11:14. Ask the students to count those with blue eyes versus those with brown eyes and write down the answers on the board. Pick out other random ratios for the students to count, and write them on the board. Reduce all the ratios to see if any are proportional, and illustrate that life and nature don't always cooperate to give proportional ratios.
Draw a simple table with two columns using a simple made-up ratio, such as the price for 10 pounds of potatoes. If $5 can be exchanged for 10 pounds of potatoes, then the ratio of dollars to pounds is 5:10, meaning that $1 will purchase 2 pounds, for a reduced ratio of 1:2. Ask the students to calculate the how many dollars can be exchanged for 15, 20, 25, 30, and 50 pounds of potatoes, and write down all the ratios in the columns of the table. Show that no matter how the numbers change, all the ratios are proportional, and all will reduce to 1:2.