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This lesson taught in Ms. Shuster's, Ms. Apo's and Ms. Flory's classes combines measuring to the nearest 1/4 inch and adding fractions with like denominators. The red, light green, yellow, black and orange Cuisenaire rods were chosen because they can be measured to the nearest 1/4 inch. Measuring to a fraction of an inch poses many challenges because the typical ruler partitions an inch into sixteenths. It is easy for students to decipher a half inch because the line is typically longer and students are comfortable with determining one half of many lengths. Fourths are more difficult because the students must ignore the lines that mark the sixteenths and the eighths. Before measuring, we talked about the logic of the inch partitions. We then partitioned the copy of the ruler into fourths by exagerating the lines so that the students could clearly see that the inch had been partitioned into four equal segments (see below). The class then measured the five Cuisenaire rods, agreeing on the measurements (measuring to the nearest quarter inch does not mean that the lengths are exact). We agreed on the following measurements:

red = 3/4 inch
light green = 1 1/4 inches
yellow = 2 inches
black = 2 3/4 inches
orange = 4 inches

In this example, the student can reason that there is one whole, and then there is 1/4 and 3/4 which makes another whole. Therefore, the total length is two wholes, or 2 inches.

In this example, the student can reason that there are 2 wholes and 1 whole. Together that makes 3 wholes. Combining 3/4 and 1/4 makes another whole, resulting in 4 wholes.

Instead of explaining to students how to add fractions computationally, we relied on the measurements they found with the rulers. The only students who got into trouble were the ones who departed from using the measuring, instead mistakenly adding fractions like this:
3/4 + 3/4 = 6/8. In subsequent lessons, students will be shown how to add fractions with like denominators computationally. This lesson was more to have them discover on their own how to add fractions and for them to reason, i.e. that 1/4 and 3/4 combined is one whole.

Indicators:
6.4.5.4 add and subtract fractional numbers with like denominators, explaining the process and recording the results.

3.4.2.1 use standard units (yards, meters, and other units) to measure objects.