Numbers that are slightly adjusted to create groups of numbers that are easy to compute mentally

a pattern or sequence of numbers in order without interuption

the set of positive numbers that begins at one and increases by increments of one each time (1,2,3...)

the remaining amount after the subtrahend has been subtracted from the minuend. The answer to a subtraction problem.

A mathematical statement composed of equivalent expressions separated by an equal sign

Rounding to determine an approximate value

A mathematical phrase, with no equal sign or comparison symbol, that may contain a number(s), and unknown(s), and/or operator(s)

Efficient application of procedures with accuracy

A number from which another number will be subtracted

a linear measurement of the distance around the outer edge of a figure

A closed figure with at least 3 sides

A type of estimation with specific rules for determining the closest value

A number to be subtracted from a minuend

The total when 2 or more addends are joined. The answer to an addition problem

The set of counting (natural) numbers and zero (0,1,2,3...)