Ahava~Love Assembly

Grade 2 Mathematics Week 8 | Teacher Guide

Grade 2 | MATHEMATICS

WEEK 8 • TEACHER GUIDE AND ANSWER KEY • DAYS 36–40

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 40, read aloud if needed but give no hints.

Week 8 Student Textbook | Week 8 Practice Workbook | Week 8 Teacher Guide | Week 7 Student Textbook | Week 9 Student Textbook | Grade 2 index

Day 36: Measure in Inches

Standard: Grade 2 Math Standard 17, 2.M.A.17

Practice record: Ruler readings, printed on the Week 8 Practice Workbook.

Worked example: A crayon starts at 0 and ends at the 3 on a ruler. How long is it? Worked answer: The crayon is 3 inches long.

  1. 2 inches.
  2. 6 inches.
  3. 5 inches (from 1 to 6 is 5 inches).
  4. The spoon (6 inches).
  5. If the object starts at 0, the number at the other end is its length. If it starts somewhere else, the number at the end is too big, like the marker, which ends at 6 but is only 5 inches long. Accept any answer about starting at 0.

Teaching note: Hands-on task answers vary. Check that the child lines up the end with 0 and rounds to the closer inch. Question 4: the spoon is the longest object (6 inches).

Day 37: Centimeters and Meters

Standard: Grade 2 Math Standard 17, 2.M.A.17

Practice record: Centimeter ruler readings, printed on the Week 8 Practice Workbook.

Worked example: A paper clip starts at 0 and ends at 3 on the centimeter side of a ruler. How long is it? Worked answer: The paper clip is 3 centimeters long.

  1. 9 centimeters.
  2. 12 centimeters.
  3. 8 centimeters (from 2 to 10).
  4. 100 centimeters.
  5. Meters. A hallway is long, so meters give a smaller, easier number to count and record. Centimeters are for small objects. Accept meters with a reason about length.

Teaching note: Let the child find something about 1 centimeter wide (a fingertip) and something about 1 meter long (a big step) to build a sense of each unit.

Day 38: Choose a Tool and Collect Data

Standard: Grade 2 Math Standard 17, 2.M.A.17

Worked example: Which tool would you use to measure the length of a couch? Worked answer: A yardstick or a measuring tape.

  1. A 12-inch ruler.
  2. A measuring tape (it bends around the pumpkin).
  3. 12 inches.
  4. 3 feet.
  5. A table is longer than 12 inches. With a ruler you would have to move it again and again, which can cause mistakes. A yardstick covers 36 inches at once. Accept any answer about the table being long.

Teaching note: Keep the child’s My 10 Measurements table. The Day 46 lesson uses it to make a line plot. Check that all 10 rows are filled, each length is a whole number of inches, and no length is more than 12 inches.

Day 39: One Object, Two Units

Standard: Grade 2 Math Standard 18, 2.M.A.18

Practice record: One object, two units, printed on the Week 8 Practice Workbook.

Worked example: A card is 4 inches long. Is it about 10 centimeters or about 2 centimeters long? Worked answer: About 10 centimeters.

  1. 6 inches.
  2. 23 centimeters.
  3. Centimeters (28 is larger than 11).
  4. 36 inches (12 + 12 + 12).
  5. A centimeter is smaller than an inch, so it takes more centimeters to cover the same notebook. The smaller the unit, the larger the number. Accept any answer that says centimeters are smaller units.

Teaching note: The table values are rounded to the nearest whole unit. Hands-on answers vary; the centimeter number should be about 2 to 3 times the inch number.

Day 40: Independent Check: Measuring Length

Standard: Grade 2 Math Standard 17, 2.M.A.17; Grade 2 Math Standard 18, 2.M.A.18

Practice record: Ruler readings, printed on the Week 8 Practice Workbook.

Worked example: A pencil starts at 0 and ends at 7 on an inch ruler. How long is it? Worked answer: 7 inches.

  1. 5 inches.
  2. 14 centimeters.
  3. 7 inches (from 2 to 9).
  4. A measuring tape.
  5. Centimeters are smaller than inches, so the book must measure more than 10 centimeters, not fewer. 4 is less than 10, so Sam is wrong. (The book is about 25 centimeters.) Accept any answer that says the centimeter number must be larger.

Teaching note: Independent check: read aloud if needed, but do not help with the answers. Question 3 does not start at 0.

Week 8 Student Textbook | Week 8 Practice Workbook | Week 8 Teacher Guide | Week 7 Student Textbook | Week 9 Student Textbook | Grade 2 index