Students can make longer fraction strips than those provided in the Student Activity Book. (Some teachers have used sentence strips.) Note that the strips for fifths and tenths made in Lesson 2 are made by measuring, not folding.
Therefore, it is helpful if the length of the strips you use is a multiple of ten centimeters so that the strips can easily be divided into fifths and tenths by measuring. For example, the strips provided in the Student Activity Book are 20 cm long. The strips can be divided into tenths by marking off 2-cm pieces.
Represent and Name Fractions. To begin this lesson, assess students' prior knowledge about representing and naming fractions. Draw a rectangle on a display. Divide the rectangle in half and shade one part of the rectangle.
- What part of the rectangle is shaded? (1/2)
Write the fraction under the shaded part of the rectangle as shown in Figure 2.
Draw a second rectangle and divide it into two obviously unequal pieces as shown in Figure 3.
- Are each of these parts 1/2 of the rectangle? (These pieces are not halves of the rectangle because they are not equal shares.)
If you feel students need other examples of fractions, draw additional rectangles, dividing them to represent various fractions. For example:
Divide a rectangle into four equal parts.
Shade one part (1/4) of the rectangle and ask:
- How much of the rectangle is shaded? (1/4)
- How much of the rectangle is not shaded? (3/4)
Divide a rectangle into three equal parts.
Shade two parts (2/3) of the rectangle and ask:
- How much of the rectangle is shaded? (2/3)
- How much of the rectangle is not shaded? (1/3)
Kid Fractions. Another way to review fractions is to ask five students, some boys and some girls, to stand in the front of the room. Ask students to identify the fraction of the students who are boys and the fraction who are girls. This activity can be repeated using a different number of students or different attributes each time.
- What fraction of the students standing have brown hair?
- What fraction of the students standing are wearing red?
As students call out fractions, write them on the board. Identify the bottom number of each fraction as the denominator. Explain that the denominator tells you the number of equal pieces (or parts) into which the whole is divided. Identify the top number of each fraction as the numerator. Explain that the numerator tells you how many pieces (or parts) you are interested in.
Observe the discussion in Part 1 of the lesson to assess students' prior knowledge of and abilities to use words and numbers to name fractions [E2]. Use this information to guide the pace and support throughout the rest of the unit.
Targeted practice for this Expectation is provided in Lesson 7. The Show Me game in Lesson 2 also provides targeted practice.
The unit whole for the fractions in the Kid Fractions section is slightly different than with the fraction strips. With fraction strips, the unit whole is the full strip, which is a continuous item. When finding the fraction of students with brown hair, however, the unit whole is the group of 5 students standing in front of the room. This is a set of discrete (or separate) items. Students may need some clarification that sometimes the whole may be one item; other times it may be a set of items.
