You can unlock your iPhone for use with different carriers. Unlocking means that you can use your phone with a different carrier. An unlocked phone is sometimes called a SIM-Free or contract-free phone.hen you'll back up, erase, and restore your iPhone to unlock it. Start the process: 1  See if your carrier offers unlocking. 2  Only your carrier can unlock your iPhone. 3  Contact your carrier and request an unlock. 4  You might need to meet requirements to qualify for unlocking.
Rounding policies that everyone agrees with: If you are rounding a number to a certain degree of significant digits, and if the number following that degree is less than five the last significant figure is not rounded up, if it is greater than 5 it is rounded up.
Significant Figure Rules. 1  Non-zero digits are always significant. 2  All zeros between other significant digits are significant. 3  The number of significant figures is determined starting with the leftmost non-zero digit.  The rightmost digit of a decimal number is the least significant digit or least significant figure.