Ahava~Love Assembly

Grade 2 Mathematics Week 14 | Teacher Guide

Grade 2 | MATHEMATICS

WEEK 14 • TEACHER GUIDE AND ANSWER KEY • DAYS 66–70

Read each lesson aloud with the child and model the worked example before practice. Do not show this key during practice. Accept oral, drawn or written answers where the child cannot yet write the whole answer. On Day 70, read aloud if needed but give no hints.

Week 14 Student Textbook | Week 14 Practice Workbook | Week 14 Teacher Guide | Week 13 Student Textbook | Grade 2 index

Day 66: Rows and Columns of Squares

Standard: Grade 2 Math Standard 26, 2.G.A.26

Practice figure: Rectangles M and N, printed on the Week 14 Practice Workbook. M has 3 rows of 4 squares (12 in all). N, when the lines are drawn, has 2 rows of 5 squares (10 in all).

Worked example: A rectangle has 2 rows with 3 squares in each row. How many squares are there? Worked answer: 6 squares.

  1. 12 squares.
  2. 10 squares.
  3. 16 squares.
  4. 8 squares (12 – 4 = 8).
  5. If the squares were different sizes, counting them would not tell how big the rectangle is, and two rectangles could not be compared fairly. Equal squares make every count mean the same amount. Accept any answer about fair or equal counting.

Teaching note: Let the child shade one row in one color and one column in another color to see the difference.

Day 67: Count Squares with Repeated Addition

Standard: Grade 2 Math Standard 26, 2.G.A.26; Grade 2 Math Standard 4, 2.OA.C.4; Grade 2 Math Standard 4, 2.OA.C.4a

Practice figure: Rectangle P, printed on the Week 14 Practice Workbook. P has 4 rows of 3 squares: 3 + 3 + 3 + 3 = 12.

Worked example: A rectangle has 3 rows with 2 squares in each row. Write an addition equation for the total. Worked answer: 2 + 2 + 2 = 6.

  1. 3 + 3 + 3 + 3 = 12.
  2. 4 + 4 + 4 = 12.
  3. 5 + 5 + 5 = 15.
  4. 2 + 2 + 2 + 2 = 8.
  5. Both ways count the same squares, just grouped in a different direction, so the total does not change. Accept any answer that says the same squares are counted.

Teaching note: Have the child circle each row with one color and write its number beside it before writing the equation.

Day 68: Arrays and Equal Addends

Standard: Grade 2 Math Standard 4, 2.OA.C.4; Grade 2 Math Standard 4, 2.OA.C.4a

Practice figure: Arrays R and S, printed on the Week 14 Practice Workbook. R: 3 + 3 + 3 = 9. S: 4 + 4 = 8.

Worked example: An array has 2 rows with 3 dots in each row. Write an equation for the total. Worked answer: 3 + 3 = 6.

  1. 3 + 3 + 3 = 9.
  2. 4 + 4 = 8.
  3. 25 dots (5 + 5 + 5 + 5 + 5).
  4. 3 + 3 + 3 + 3 = 12 chairs.
  5. Turning the array on its side does not add or take away any dots. 2 + 2 + 2 + 2 + 2 = 10 and 5 + 5 = 10. Accept any answer that shows both totals are 10 or says the same dots are counted.

Teaching note: Build each array with coins, beans or blocks, then turn it a quarter turn to show the rows becoming columns.

Day 69: Cover a Rectangle with Squares

Standard: Grade 2 Math Standard 26, 2.G.A.26

Worked example: A tray is covered with 2 rows of 4 sticky notes. How many sticky notes are there? Worked answer: 8 sticky notes.

  1. 20 notes.
  2. 5 + 5 + 5 + 5 = 20.
  3. 25 notes.
  4. 12 notes (4 + 4 + 4).
  5. If notes overlap, some space is counted twice. If there are gaps, some space is not counted at all. Either way the count would not show the real size. Accept any answer about counting the space correctly.

Teaching note: Results vary with the object. Check that the equation matches the rows and squares the child counted. Use the observation checklist below.

Hands-on task observation checklist (Cover a book or tray with squares). Check each item you observe. Four or five items shows the child met the task goal; two or three means repeat the task with support.

  • ☐ Child used squares that are all the same size.
  • ☐ Child left no gaps and no overlaps.
  • ☐ Child counted the rows and the squares in a row.
  • ☐ Child wrote an equation with equal addends.
  • ☐ Child’s total matches the squares used.

Day 70: Independent Check: Rows, Columns and Arrays

Standard: Grade 2 Math Standard 26, 2.G.A.26; Grade 2 Math Standard 4, 2.OA.C.4; Grade 2 Math Standard 4, 2.OA.C.4a

Practice figure: Rectangle U and Array V, printed on the Week 14 Practice Workbook. U: 2 + 2 + 2 + 2 = 8. V: 5 + 5 + 5 = 15.

Worked example: A rectangle has 3 rows with 3 squares in each row. How many squares are there? Worked answer: 9 squares.

  1. 8 squares.
  2. 5 + 5 + 5 = 15.
  3. 4 squares.
  4. 4 + 4 + 4 + 4 = 16.
  5. Add the rows: 3 + 3 + 3 + 3 + 3 = 15. Or add the columns: 5 + 5 + 5 = 15. Accept any two correct ways that reach 15.

Teaching note: Independent check: read aloud if needed, but give no hints.

Week 14 Student Textbook | Week 14 Practice Workbook | Week 14 Teacher Guide | Week 13 Student Textbook | Grade 2 index

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