Terminology
New or Recently Introduced Terms and Symbols

 About (with reference to rounding and estimation, an answer that is not precise)

 Addend (the numbers that are added together in an addition equation, e.g., in 4 + 5, the numbers 4 and 5 are the addends)  Capacity (the amount of liquid that a particular container can hold)

 Continuous (with reference to time as a continuous measurement)

 Endpoint2 (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)

 Interval (time passed or a segment on the number line)

 Halfway (with reference to a number line, the midpoint between two numbers, e.g., 5 is halfway between 0 and 10)

 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?”)

 Round3 (estimate a number to the nearest 10 or 100 using place value)

 Second (a unit of time)

 Standard algorithm (for addition and subtraction)

 ≈ (symbol used to show that an answer is approximate)