Grade 2 | MATHEMATICS
WEEK 15 • STUDENT TEXTBOOK • DAYS 71–75
Read each lesson with a parent or teacher and study the worked example. Then answer the questions for that day in the Week 15 Practice Workbook.
Week 15 Student Textbook | Week 15 Practice Workbook | Week 15 Teacher Guide | Week 14 Student Textbook | Week 16 Student Textbook | Grade 2 index
Day 71: Halves of Circles and Rectangles
Equal shares are parts of a whole that are all the same size. When a whole is cut into 2 equal shares, each share is a half. We say each share is half of the whole, or one half.
Two halves make one whole. If the parts are not the same size, they are not halves, even when there are 2 of them. Check that each part is the same size before you name it.
Worked example: A pizza is cut into 2 equal pieces. What is each piece called?
- There are 2 equal shares.
- Each of 2 equal shares is called a half.
Worked answer: Each piece is a half.
Day 72: Thirds and Fourths
When a whole is cut into 3 equal shares, each share is a third. We say a third of the whole, or one third. When a whole is cut into 4 equal shares, each share is a fourth. A fourth is also called a quarter.
The more equal shares you cut a whole into, the smaller each share is. A fourth of a sandwich is smaller than a half of the same sandwich.
Worked example: A cracker is broken into 3 equal pieces. What is each piece called?
- There are 3 equal shares.
- Each of 3 equal shares is called a third.
Worked answer: A third.
Day 73: Describe the Whole; Equal or Not Equal
A whole can be described by its equal shares. A circle cut into halves is two halves. A rectangle cut into thirds is three thirds. A square cut into fourths is four fourths. Each of these is one whole.
Shares are equal only when they are all the same size. If you count the parts but they are different sizes, you cannot call them halves, thirds or fourths.
Worked example: How many halves make one whole?
- A whole cut into 2 equal shares has 2 halves.
- Put the 2 halves together to make the whole.
Worked answer: Two halves.
Day 74: Equal Shares Can Have Different Shapes
Equal shares of the same whole do not have to be the same shape. A square cut in half from side to side makes 2 rectangles. The same square cut in half from corner to corner makes 2 triangles.
Both ways make halves, because in each case the square is cut into 2 equal shares. Each share covers exactly half of the square, whatever its shape.
Worked example: A square napkin is folded corner to corner into 2 equal shares. What is each share called?
- The napkin is cut into 2 equal shares.
- Each of 2 equal shares is a half, whatever its shape.
Worked answer: A half.
Day 75: Independent Check: Equal Shares
Today you will answer on your own.
Use what you learned this week: halves, thirds and fourths, describing the whole, equal and unequal shares, and equal shares with different shapes.
Worked example: How many fourths make one whole?
- A whole cut into 4 equal shares has 4 fourths.
- Put the 4 fourths together to make the whole.
Worked answer: Four fourths.
Week 15 Student Textbook | Week 15 Practice Workbook | Week 15 Teacher Guide | Week 14 Student Textbook | Week 16 Student Textbook | Grade 2 index