How many amendments does the U.S. Constitution have?

Why this is the answer

Twenty-seven is the number to remember, and it splits into two parts that make it easier to keep. The first ten amendments arrived together in 1791 as the Bill of Rights. Seventeen more followed over the next two centuries. Several of those later seventeen changed who is free and who can vote. The Thirteenth, ratified in 1865, abolished slavery. The Fifteenth, ratified in 1870, barred the federal government and the states from denying the vote because of race, color or previous condition of servitude. The Nineteenth, in 1920, did the same for sex, and the Twenty-sixth, in 1971, protected the vote of citizens eighteen and older. The most recent addition has an unusual story. The Twenty-seventh Amendment says that a law changing the pay of senators and representatives cannot take effect until after the next House election. Congress first proposed it in 1789, together with the proposals that became the Bill of Rights, and it was not ratified until 1992, 203 years after it was proposed. The total stays low because amending the Constitution is hard. Three-fourths of the states, 38 of the 50, have to approve each amendment, and six times an amendment has passed Congress only to fall short in the states. This is one of the 20 asterisk questions, part of the shorter list for applicants who qualify for the 65/20 special consideration. The answer itself needs no explanation at the interview. Say the number, "twenty-seven," and you are done. Be careful not to grab a nearby number. Ten is the size of the Bill of Rights, not the full count of amendments, and fifty is the number of states. A quick sum confirms it before you answer: ten from 1791 plus seventeen afterward makes twenty-seven, and the last of them came in 1992.