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Number Sentence

An equation is a mathematical statement, in symbols, that
two things are the same (or equivalent). Equations are written
with an equal sign, as in    2 + 3 = 5

An inequality is a statement about the relative size or order of
two objects. Could be greater than or less than
Example:  4 x 4 < 20

This inequality says 4 times 4 is less than < 20


Equation and inequality are number sentence
Example: 2 + 3 = 5       4 x 4 < 20    These are all number
sentence.  

Some number sentence will ask you to find missing
numbers
12 + ? > 30  what is the missing number

A. 13        B. 15           C. 20
the missing number in this number sentence is - c. 20

Number sentence can be true or not true
Example: 4 + 6 = 8   This number sentence is not true,
because 4 plus 6  equal  10 not 8

Number sentence can be greater than or less than
< (less than sign)                 > (greater than sign)


other operation symbols in number sentence
≠ not equal to
≥ is greater than or equal to
≤ is less than or equal to



Typical number sentence homework.
If John has three apples. He gives two apples to Jane. Write
a number sentence for this problem. Answer: 3 - 2 = 1

Jenny has 7 marbles and Kenny has 5.  How many do they
have together? Write a number sentence for this problem. 
Answer:  7 + 5 = 12

What number is missing to make this number sentence true
237 < 2 __ 8
A O       C2        D3         B1

Answer is D3   238