Ahava~Love Assembly

Grade 2 Mathematics Week 15 | Teacher Guide

Grade 2 | MATHEMATICS

WEEK 15 • TEACHER GUIDE AND ANSWER KEY • DAYS 71–75

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 75, read aloud if needed but give no hints.

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

Standard: Grade 2 Math Standard 27, 2.G.A.27

Practice figure: Shapes A, B, C, D and E, printed on the Week 15 Practice Workbook. A and C are cut into halves. B and D are cut into 2 parts that are not equal. E is blank for drawing.

Worked example: A pizza is cut into 2 equal pieces. What is each piece called? Worked answer: Each piece is a half.

  1. Shapes A and C.
  2. 2 pieces.
  3. Drawings vary: one line through the middle, either from top to bottom or from side to side, making 2 equal shares.
  4. One half (half of the sandwich).
  5. The line is not in the middle, so one part is bigger than the other. Halves must be 2 equal shares. Accept any answer saying the parts are not the same size.

Teaching note: Fold a paper circle and a paper rectangle in half and open them to show the 2 equal shares along the fold.

Day 72: Thirds and Fourths

Standard: Grade 2 Math Standard 27, 2.G.A.27

Practice figure: Shapes A, B, C and D, printed on the Week 15 Practice Workbook. A is in thirds, B in fourths, C in thirds with one third shaded, D in fourths.

Worked example: A cracker is broken into 3 equal pieces. What is each piece called? Worked answer: A third.

  1. 3 equal shares; each share is a third.
  2. A fourth (also called a quarter).
  3. third (One third of the rectangle is shaded.)
  4. A fourth, or a quarter, of the circle.
  5. A third is bigger. When the same whole is cut into fewer equal shares, each share is bigger. Accept any answer saying 3 shares of the same whole are bigger than 4 shares.

Teaching note: Use paper circles and strips. To fold a strip into 3 equal parts, roll it into an S shape, line up the edges and press flat.

Day 73: Describe the Whole; Equal or Not Equal

Standard: Grade 2 Math Standard 27, 2.G.A.27

Practice figure: Shapes A, B, C and D, printed on the Week 15 Practice Workbook. A shows fourths and C shows halves. B has 3 unequal parts and D has 4 unequal parts.

Worked example: How many halves make one whole? Worked answer: Two halves.

  1. Shapes A and C.
  2. four (four fourths)
  3. 3 thirds (three thirds).
  4. 2 fourths (two fourths, the same amount as one half).
  5. Mo is not right. Thirds must be 3 equal shares, and the parts of Shape B are different sizes. Accept any answer saying the parts are not equal.

Teaching note: Cut a paper rectangle into fourths, then put the pieces back together so the child sees that four fourths make one whole.

Day 74: Equal Shares Can Have Different Shapes

Standard: Grade 2 Math Standard 27, 2.G.A.27a

Practice figure: Shapes A, B, C, D and E, printed on the Week 15 Practice Workbook. A and B are in halves (rectangles and triangles). C and D are in fourths (small squares and triangles). E is blank.

Worked example: A square napkin is folded corner to corner into 2 equal shares. What is each share called? Worked answer: A half.

  1. Yes and yes. Each shape is cut into 2 equal shares, so every share is a half.
  2. A triangle.
  3. Shape C: a small square. Shape D: a triangle.
  4. Drawings vary. Example: three lines from top to bottom that make 4 equal strips. Any 4 equal shares are correct.
  5. Each one is 1 of 2 equal shares of the same square, so they are the same size even though their shapes are different. Accept any answer saying they are the same size or each is 1 of 2 equal shares.

Teaching note: Use paper squares that are exactly the same size, such as square sticky notes. Use the observation checklist below.

Hands-on task observation checklist (Fold and cut paper squares two ways). 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 cut squares of the same size.
  • ☐ Child folded one square side to side and one corner to corner.
  • ☐ Child cut on the fold lines.
  • ☐ Child named the shape of each share.
  • ☐ Child explained that both kinds of shares are halves.

Day 75: Independent Check: Equal Shares

Standard: Grade 2 Math Standard 27, 2.G.A.27; Grade 2 Math Standard 27, 2.G.A.27a

Practice figure: Shapes A, B, C, D and E, printed on the Week 15 Practice Workbook. A is in thirds; B has 2 unequal parts; C is in fourths with one fourth shaded; D is in halves; E is blank.

Worked example: How many fourths make one whole? Worked answer: Four fourths.

  1. A third.
  2. No. The line does not go through the middle, so the 2 parts are not the same size.
  3. One fourth (a quarter) of the circle.
  4. Drawings vary: two evenly spaced lines from top to bottom or from side to side, making 3 equal shares.
  5. The square is cut into 2 equal shares, and each triangle is one of them. Equal shares of the same whole can have different shapes. Accept any answer about 2 equal shares.

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

Week 15 Student Textbook | Week 15 Practice Workbook | Week 15 Teacher Guide | Week 14 Student Textbook | Week 16 Student Textbook | Grade 2 index