Mathematics Unit 6: Division, Map Reference Frames, Measurement of Angles
January 24–February 20, 2014
Inquiry Question:
- How do you decide when close is close enough?
- What does it mean to do a 180? A 360? A 720?
Essential Learning Goals:
- Represent and solve problems involving multiplication and division. (ELG.MA.4.PFA2)
- Multiply whole numbers of up to four digits by one-digit whole numbers and multiply two, two-digit numbers. Multiply or divide to solve word problems involving multiplicative comparison, distinguishing multiplicative comparison from additive comparison. Find whole number quotients and remainders with up to four-digit dividends and one-digit divisors. (ELG.MA.4.OC3)
- Recognize angles as geometric shapes that are formed from two rays sharing a common endpoint; measure angles; recognize angle measure as additive. (ELG.MA.4.MRF1)
Concepts:
Angle measurement, measurement, decomposition, multiplication, division
Academic Vocabulary: Right-click on vocabulary to look it up in the dictionary.
Measure, record, convert, sketch, demonstrate, describe, apply, represent, express, right angle
Technical Vocabulary: Right-click on vocabulary to look it up in the dictionary.
Angle, acute, right, and obtuse angles, fraction, intersection, vertex, degrees, equivalent, division, multiplication, protractor, two-column table, partial quotient, remainder, clockwise
Technology:
- Rectangle Division: http://nlvm.usu.edu/en/nav/frames_asid_193_g_2_t_1.html?from=grade_g_2.html (visualize and practice dividing numbers using area representations)
- Angle Sums: http://illuminations.nctm.org/ActivityDetail.aspx?ID=9 (visuals for three to eight-sided figures with angles)
Common Misconception:
Students might be confused about which number to use when determining measures of angles using protractors because most protractors have a double set of numbers. Students should decide first whether angles appear to be less than or greater than the measure of a right angle (90°). If angles appear to be less than 90°, they are acute angles and their measures range from 0° to 89°. If angles appear to be greater than 90°, they are obtuse angles and their measures range from 91° to 179°. Ask questions about appearances of angles to help students determine which number to use.