Ahava~Love Assembly

Grade 2 Mathematics Week 19 | Teacher Guide

Grade 2 | MATHEMATICS

WEEK 19 • TEACHER GUIDE AND ANSWER KEY • DAYS 91–95

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 95, read aloud if needed but give no hints.

Week 19 Student Textbook | Week 19 Practice Workbook | Week 19 Teacher Guide | Week 18 Student Textbook | Grade 2 index

Day 91: Choose a Tool; Measure in Two Units

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

Worked example: A ribbon is 4 feet long, which is 48 inches. Which unit gives the larger number? Worked answer: Inches (48 is more than 4).

  1. A measuring tape.
  2. About 15 centimeters.
  3. 200 centimeters.
  4. 23 centimeters.
  5. A centimeter is a smaller unit than an inch, so it takes more centimeters to cover the same length.

Teaching note: One inch is about 2 and a half centimeters, so 6 inches is about 15 centimeters. A meter is 100 centimeters.

Day 92: Estimate, Then Measure and Compare

Standard: Grade 2 Math Standard 19, 2.M.A.19; Grade 2 Math Standard 20, 2.M.A.20

Worked example: A rope is 50 inches long and a jump rope is 38 inches long. How much longer is the rope? Worked answer: 12 inches longer.

  1. About 7 feet.
  2. 5 centimeters longer.
  3. Too short, by 2 inches.
  4. 9 inches shorter.
  5. An estimate helps you check whether your measurement makes sense. If the measurement is very far from the estimate, you can measure again. Accept any reasonable reason.

Teaching note: Let the child check the door estimate with a measuring tape if one is available.

Day 93: Length Word Problems on a Number Line

Standard: Grade 2 Math Standard 21, 2.M.B.21; Grade 2 Math Standard 22, 2.M.B.22

Practice figure: Number line: Mia’s ribbon, printed on the Week 19 Practice Workbook. Number line 0 to 60 by 10s, with a jump from 0 to 35 labeled +35 and a jump from 35 to 52 labeled +17.

Worked example: A worm crawled 20 centimeters, then 15 more centimeters. How far did it crawl? Worked answer: 35 centimeters.

  1. 52 inches.
  2. 47 centimeters.
  3. 67 feet.
  4. 26 meters.
  5. Start at 72 and jump back 25 to land on 47, so the board is 47 centimeters long. Accept a number line that starts at 72 and jumps back 25 (or jumps forward from 47 to 72).

Teaching note: The child may draw the item 5 number line in the answer space. Any start and jump that match the problem are correct.

Day 94: Hands-On: Hand Spans on a Line Plot

Standard: Grade 2 Math Standard 15, 2.DA.A.15; Grade 2 Math Standard 15, 2.DA.A.15a; Grade 2 Math Standard 17, 2.M.A.17

Practice record: Hand spans of 10 people (inches), printed on the Week 19 Practice Workbook.

Practice figure: Line plot to complete: hand spans of 10 people, printed on the Week 19 Practice Workbook.

Worked example: Five hand spans are 5, 6, 6, 6 and 7 inches. How many X marks go above 6? Worked answer: 3 X marks.

  1. 4.
  2. 6 inches.
  3. 3 (two at 7 inches and one at 8 inches).
  4. 2 more (4 – 2).
  5. The line plot is marked only in whole inches, so every measurement needs to land on a whole number to have a place for its X. Accept any answer about matching the whole-number marks.

Teaching note: Check the completed sample line plot: 3, 4, 2 and 1 X marks above 5, 6, 7 and 8, and none above 4 or 9. The family line plot uses the child’s own data, so answers vary. Use the observation checklist below.

Hands-on task observation checklist (Measure hand spans and make a line plot). 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 measured each hand span to the nearest inch.
  • ☐ Child recorded each length in the table.
  • ☐ Child drew one X for each person.
  • ☐ Child stacked X marks for equal lengths.
  • ☐ Child named the most common length.

Day 95: Independent Check: Measurement and Line Plots

Standard: Grade 2 Math Standard 18, 2.M.A.18; Grade 2 Math Standard 19, 2.M.A.19; Grade 2 Math Standard 20, 2.M.A.20; Grade 2 Math Standard 21, 2.M.B.21; Grade 2 Math Standard 22, 2.M.B.22; Grade 2 Math Standard 15, 2.DA.A.15; Grade 2 Math Standard 15, 2.DA.A.15a

Practice figure: Line plot: lengths of 8 feathers, printed on the Week 19 Practice Workbook. X marks: 2 above 6, 3 above 7, 2 above 8, 1 above 9 (centimeters).

Worked example: Which is longer: 1 foot or 1 inch? Worked answer: 1 foot.

  1. 3.
  2. 3 centimeters (9 – 6).
  3. 6 centimeters longer.
  4. 32 inches.
  5. 1 foot is 12 inches, so 3 feet is 12 + 12 + 12 = 36 inches. They used different units for the same length.

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

Week 19 Student Textbook | Week 19 Practice Workbook | Week 19 Teacher Guide | Week 18 Student Textbook | Grade 2 index