Today Aiden and I worked on the circumference of a circle. I began by asking him about his prior knowledge, what's a circumference, diameter, radius? We recalled the formulas are C=Pi*D and/or C=2*Pi*r. We considered the measure of a tire's circumference and compared it to the linear distance. Aiden recognized these values are equal. We were given the measure of the circumference (28in) and asked to find the diameter of the bicycle tire. Aiden knew to divide 28 by Pi. Next we considered different variations of the circumference formula. That C=Pi*D is the same as Pi=C/D. For a visual application, I gave Aiden string and asked him to cut it at a whole number length, he chose 12 inches. He created a circle with the string. Then he used the ruler to measure the diameter. He then divided the circumference 12 by the diameter measure and we found the ratio as 3.09 (our goal was to get to Pi=3.14, so we were close). We ended with a challenge problem involving rates of rotation. Aiden was given the rate of a gear with a diameter of 6cm as rotation 2 revolutions per second. Then had to use that to find out the rate that a circle with 2cm would be. We determined in 1 second the larger circle traveled 12Pi cm in 1 second. This would imply the smaller circle would rotate 6 times in that time span of one minute. In other words, the smaller circle revolves 6 times in 1 minute.