Grade 2 | MATHEMATICS
WEEK 3 • STUDENT TEXTBOOK • DAYS 11–15
Read each lesson with a parent or teacher and study the worked example. Then answer the questions for that day in the Week 3 Practice Workbook.
Week 3 Student Textbook | Week 3 Practice Workbook | Week 3 Teacher Guide | Week 2 Student Textbook | Week 4 Student Textbook | Grade 2 index
Day 11: Even and Odd: Make Pairs
Put objects into pairs, two at a time. If every object has a partner, the number is even. If one object is left over with no partner, the number is odd.
You can check any group up to 20 this way with counters, beans or buttons. Even numbers end in 0, 2, 4, 6 or 8. Odd numbers end in 1, 3, 5, 7 or 9.
Worked example: Is 9 even or odd?
- Lay out 9 counters.
- Make pairs: 4 pairs use 8 counters.
- 1 counter is left with no partner.
Worked answer: 9 is odd.
Day 12: Even Numbers Are Doubles
An even number can be split into two equal groups. We write it as a double, using the same number twice: 6 = 3 + 3.
This kind of equation is called a sum of two equal addends. Odd numbers cannot be split into two equal groups of whole objects.
Worked example: Write 10 as a sum of two equal addends.
- Split 10 counters into two equal groups.
- Each group has 5.
- Write the equation.
Worked answer: 10 = 5 + 5.
Day 13: Arrays: Rows and Columns
An array is a set of objects in equal rows. A row goes across. A column goes up and down.
To find the total, add the same number for each row. An array with 3 rows of 4 has 4 + 4 + 4 = 12 objects. In Grade 2, arrays have up to 5 rows and up to 5 columns.
Worked example: An egg tray has 2 rows with 5 eggs in each row. How many eggs are there?
- There are 2 rows.
- Each row has 5 eggs.
- Add one 5 for each row: 5 + 5 = 10.
Worked answer: There are 10 eggs.
Day 14: Write an Equation for an Array
You can write an equation for an array. Add the number in each row, once for every row, and write the total after the equal sign.
An array with 4 rows of 3 has the equation 3 + 3 + 3 + 3 = 12. You can also add the columns: 4 + 4 + 4 = 12. Both ways give the same total.
Worked example: Write an equation for a window with 2 rows of 4 panes.
- Each row has 4 panes.
- There are 2 rows, so add 4 two times.
- 4 + 4 = 8.
Worked answer: 4 + 4 = 8.
Day 15: Independent Check: Even, Odd and Arrays
Today you will answer on your own.
Use what you learned this week: make pairs to find even and odd, write doubles, and add equal rows in an array.
Worked example: Is 13 even or odd?
- Make pairs with 13 counters.
- 6 pairs use 12 counters, and 1 is left over.
Worked answer: 13 is odd.
Week 3 Student Textbook | Week 3 Practice Workbook | Week 3 Teacher Guide | Week 2 Student Textbook | Week 4 Student Textbook | Grade 2 index