Eureka Math Parent Tips
Second Grade Module 2
Addition and Subtraction
of length Units.
This document is being produced for the purpose
of giving parents and students in Calcasieu
Parish a better understanding of the math
concepts being taught.
In Module 2, students engage in activities
designed to deepen their conceptual
understanding of measurement and to relate
addition and subtraction to length. Their
work in Module 2 is exclusively with metric
units in order to support place value
concepts.
Louisiana Standards:
- Measure the length of an object by selecting and
using appropriate tools such as rulers, yardsticks,
meter sticks, and measuring tapes.
Measure the length of an object twice, using length units of different lengths for the two measurements;
describe how the two measurements relate to the size of the unit chosen.
Estimate lengths using units of inches, feet, centimeters, and meters.
Measure to determine how much longer one object is than another, expressing the length difference in
terms of a standard length unit.
Use addition and subtraction within 100 to solve word problems involving lengths that are given in the
same units, e.g., by using drawings (such as drawings of rulers) and equations with a symbol for the
unknown number to represent the problem.
Represent whole numbers as lengths from 0 on a number line diagram with equally spaced points
corresponding to the numbers 0, 1, 2, …, and represent whole-number sums and differences within 100
on a number line diagram.
Students will measure using first physical centimeter
units, understanding in order to get accurate
measurement, there must not be any gaps or overlaps
between consecutive length units.
They will use the mark and advance technique. It also
helps them realize that the distance between 0 and 1
on the ruler indicates the amount of space already
covered. They will create their ruler. Topic A ends with
students using their unit rulers to measure lengths,
thereby connecting measurement with a ruler.
Students use the centimeter
cube placed at the start point
and mark the end point, and
continue with no overlaps. This
helps students create a mental
benchmark for the centimeter. It
also helps them realize that the
distance between 0 and 1 on the
ruler indicates the amount of
space already covered. Hence 0,
not 1, marks the beginning of
the total length.
Second Grade Module 2
In Lesson 4, students begin using
centimeter rulers, meter sticks, and meter
tapes to measure various objects. Through
the practice of measuring various items and
learning mental benchmarks for
measurement, students organically develop
estimation skills in Lesson 5. They also
develop their skills for selecting an
appropriate measuring tool by referencing
prior knowledge of objects they have
already measured, as well as by using
mental benchmarks.
Example:
First estimate the length of the
line in centimeters using mental
benchmarks. Then measure it
line with a cm ruler to find the
actual length.
a. Estimate: ______ cm
b. Actual length: ______ cm
Measuring with Standard and Non-standard Units
Line L is _3_ paper clips.
Line L is _7_ cm long.
Line L is _2_ paper
clips longer than Line
M. (3-1= 2)
Line M doubled is
_1_ cm longer than
Line L.
Line M is _2_ paper clips.
Line M is _4_ cm long.
Words to know:
Ruler, Centimeter, Length, Length Unit, Compare, Combine,
Overlap, Longest, Shortest, End Point, Hash Mark, Meter Strip,
Standard Unit, Non-standard Unit
Common
Error:
When using rulers, young students
often begin measuring at the 1.
The start point needs to be the 0.
Second Grade Module 2
Solving addition and subtraction
word problems using the ruler.
Tape Diagram- A visual model
using rectangles to show the
relationship between
numbers.
A frog hopped 5cm forward and 3cm back then
rested on his lily pad. If the frog started at 7 on the
ruler, where did the frog stop to rest? Show your
work on the ruler.
How you can help at home…
• Estimate the lengths of various objects around
the house, such as a table, a book, a toothbrush,
etc. Next, Measure the same objects using a ruler
with inches and centimeters to compare the
estimate to the actual length.
• Measure the four sides of a square or rectangular table using
inches, and then add the four sides together to find out how long
the table is around.
• Measure two different book lengths using centimeters. Compare the
two lengths and determine how much longer one book is than the
other.