Algebra Know-It-ALL

(Marvins-Underground-K-12) #1
(c) MMIX = 1,000 + 1,000 + 9 = 2,009
(d) MMVI = 1,000 + 1,000 + 6 = 2,006


  1. The number three hundred two trillion, seventy billion, one hundred forty-nine
    million, six thousand, one hundred ten looks like this as a decimal numeral:


302,070,149,006,110

Note the placement of the commas and the ciphers. Also note that we use the American
billion, which is equivalent to a thousand million.


  1. This is a slightly whimsical problem. You can add as many ciphers as you want to the
    left of the digit 3 in the answer to the previous problem, and it does not change the
    value of the number it represents. A mathematician might write it as


...,000,000,...,302,070,149,006,110


You can keep “attaching ciphers” forever in the left-hand direction!


  1. You can make any number in the decimal system ten times as large by adding one
    cipher to its right and then repositioning the commas. Based on the numeral shown
    for the answer to Prob. 4 above, you would get


3,020,701,490,061,100


If you want to make a number a hundred times as large, add two ciphers to its right and
then reposition the commas. Starting with the numeral shown for the answer to Prob. 4,
that gives you

30,207,014,900,611,000

If you want to make a number a thousand times as large, add three ciphers to its right and
then reposition the commas. Starting with the numeral shown for the answer to Prob. 4,
that gives you

302,070,149,006,110,000


  1. The number in the final answer to Prob. 6 would be written out in words as three
    hundred two quadrillion, seventy trillion, one hundred forty-nine billion, six million,
    one hundred ten thousand. That’s based on the United States terminology where a
    billion is a thousand million, and a trillion is a million million.

  2. To solve this problem, tally the values of each digit in the decimal system and then add
    them up, as follows.

    • One times one gives you 1

    • One times two gives you 2

    • Zero times four gives you 0




Appendix B Worked-Out Solutions to Exercises: Chapters 11 to

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