GRE
The price of commodity X at the beginning of last year
The price of commodity X at the end of last year
|a+b|
|a-b|
$$\frac{nx+py}{n+p}$$
$$\frac{x+y}{2}$$
RS
ST
The remainder when 26n is divided by 4
2
$$x^{2}$$+1
x+ $$\frac{7}{8}$$
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