ENDURING UNDERSTANDINGS ESSENTIAL QUESTIONS
 The duration of an event is called elapsed
time and it can be measured
 Mass and volume are important parts of everyday life and can determined a variety of ways.
 Larger units can be subdivided into
 equivalent units (partition).
The same unit can be repeated to determine the measure (iteration).
 There is a relationship between the size of a unit and the number of units needed

(compensatory principle).
Place value is crucial when operating with numbers.
 Estimation helps us see whether or not our answers are reasonable.
Using rounding is an appropriate estimation  strategy for solving problems and estimating.
 Rounded numbers are approximate and not exact.
 Addition and subtraction are inverse
operations; one undoes the other.
 We can verify the results of our computation
 What strategies can I use to help me tell and write time to the nearest minute and
 measure time intervals in minutes?
What connections can I make between a clock and a number line?
 How can we determine the amount of time
 that passes between two events?
How can I demonstrate my understanding of the measurement of time?
 What does the liquid volume of an object tell me?
 What types of tools are used to measure volume?
 What does the mass of an object tell me about it?
 What ways can I measure mass?
 What strategies can I use to help me to solve problems involving volume or mass?
 What determines your choice of a measurement tool?
What estimation strategies are used in  measurement?
 How is the appropriate unit for measurement determined?

 by using the inverse operation.
Adding zero to a number or subtracting zero from a number does not change the original amount.
 Addition means the joining of two or more sets that may or may not be the same size.
There are several types of addition problems, see the chart above.
 The counting up strategy can be used to make change.
 Subtraction has more than one meaning. It not only means the typical “take away” operation, but also can denote finding the
difference between sets. Different subtraction situations are described in the chart above.
 How is the reasonableness of a measurement determined?
 Why are units important in measurement?
 How can I demonstrate my understanding of the measurement of volume and mass?
 Why is place value important?
 How are digits in a number related?
 What can we learn about the value of a number by examining its digits?
 How do we round numbers to the nearest ten or hundred?
 In what situations might a person want to round a number to the nearest ten?
What does it mean to round numbers to the  nearest ten?
 What estimation and mental math strategies can I use to help me solve real world problems?
How can estimation strategies help us build  our addition skills?
 How can I show what I know about addition and subtraction, problem solving, and estimation?
 What strategies are helpful when estimating sums in the hundreds?
 When will estimating be helpful to us?
 How are addition and subtraction alike and different?
 How can I learn to quickly calculate sums in my head?
 How can I use addition and subtraction to help me solve real world problems?
 How can I verify the results of an addition or
 subtraction word problem?
How do properties work in addition and subtraction problems?
 How is zero different from any other whole number you might add or subtract?

New Terminology
 About (with reference to rounding and estimation, an answer that is not precise)
 Addend (the numbers that are added together in an addition equation)
 Analog clock (a clock that displays the time of day by the position of hands on a dial)
 Capacity (the amount of liquid that a particular container can hold)
 Compose (change 10 smaller units for 1 of the next larger unit on the place value chart)
 Continuous (with reference to time as a continuous measurement)
 Endpoint (used with rounding on the number line; the numbers that mark the beginning and end of a given interval)
 Gram (g, unit of measure for weight)
 Halfway (with reference to a number line, the midpoint between two numbers, e.g., 5 is halfway between 0 and 10)
 Interval (time passed or a segment on a number line)
 Kilogram (kg, unit of measure for mass)
 Liquid volume (the space a liquid takes up)
 Liter (L, unit of measure for liquid volume)
 Milliliter (mL, unit of measure for liquid volume)
 Plot (locate and label a point on a number line)
 Point (a specific location on the number line)
 Reasonable (with reference to how plausible an answer is, e.g., “Is your answer reasonable?”)
 Rename (regroup units, e.g., when solving with the standard algorithm)
 Round (estimate a number to the nearest 10 or 100 using place value)
 Second (a unit of time)
 Standard algorithm (for addition and subtraction)
Familiar Terminology
 Centimeter (cm, unit of measurement)
 Divide (e.g., 4 ÷ 2 = 2)
 Estimate (approximation of the value of a quantity or number)
 Horizontal (with reference to how an equation is written, e.g., 3 + 4 = 7 is written horizontally)
 Measure (a quantity representing a weight or liquid volume, or the act of finding the size or amount of something)
 Mental math (calculations performed in one’s head, without paper and pencil)
 Meter (m, unit of measurement)
 Minute (a unit of time)
 Multiply (e.g., 2 X 2 = 4)
 Number line (may be vertical or horizontal, vertical number line shown below)
 Simplifying strategy (transitional strategies that move students toward mental math, e.g.,
“make ten” to add 7 and 6, (7 +3) + 3 = 13)
 Unbundle (regroup units, e.g., in the standard algorithm)
 Vertical (with reference to how an equation is written; equations solved using the standard algorithm are typically written vertically)