Every positive number a has two square roots: a, which is positive, and a, which is negative. Together, these two roots are denoted as a (see shorthand). Although the principal square root of a positive number is only one of its two square roots, the designation ''the square root'' is often used to refer to the principal square root. For positive a, the principal square root can also be written in exponent notation, as a.
does every positive number have 2 square roots?
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Answer: yes

The Canon EF-S lens mount is a derivative of the EF lens mount created for a subset of Canon digital single-lens reflex cameras with APS-C sized image sensors. It was released in 2003. Cameras with the EF-S mount are backward compatible with the EF lenses and, as such, have a flange focal distance of 44.0 mm. Such cameras, however, have more clearance, allowing lens elements to be closer to the sensor than in the EF mount. Only Canon cameras released after 2003 with APS-C sized sensors support the EF-S mount.
does all canon lenses fit all canon cameras?
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Answer: no

Large denominations of United States currency greater than $100 were circulated by the United States Treasury until 1969. Since then, U.S. dollar banknotes have only been issued in seven denominations: $1, $2, $5, $10, $20, $50, and $100.
is a 100 dollar bill the highest bill?
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Answer:
yes