Our Homeschool




Roman Numeral Fun

We don't really have a formal curriculum that we use for math.  The other day the topic of Roman Numerals came up because the books that Nathaniel reads use Roman Numerals for chapter numbers.  So I decided to come up with something simple to teach them this concept.  I printed out the letters on a sheet of cardstock.  Cut them out and "laminated" them with clear contact paper that I bought at the Dollar Tree (actually I let Nathaniel be in charge of laminating them).  Then, using permanent marker, I wrote the number equivalents on the back of each card.  I printed out the "rules" for Roman Numerals and then we sat down on the floor, went over the rules and just started playing around making different numbers and seeing who could figure it out first.  It was fun AND it really helped them retain the information.

Here are the rules I printed out:
Roman numerals are expressed by letters of the alphabet:

I want to put an interjection here:  To help them remember the order of the letters smallest to largest, we made up a little phrase:

I - I'm
V- Very
X - Xcited
L- Loonies
C - Can
D - Do
M - Math

A letter repeats its value that many times (XXX = 30, CC = 200, etc.).

A letter can only be repeated three times.

If one or more letters are placed after another letter of greater value, add that amount.

If a letter is placed before another letter of greater value, subtract that amount.
Several rules apply for subtracting amounts from Roman numerals:

          o a. Only subtract powers of ten (I, X, or C, but not V or L)

                For 95, do NOT write VC (100 – 5).
                DO write XCV (XC + V or 90 + 5)

          o b. Only subtract one number from another.

                For 13, do NOT write IIXV (15 – 1 - 1).
                DO write XIII (X + I + I + I or 10 + 3)

          o c. Do not subtract a number from one that is more than 10 times greater (that is, you can
                subtract 1 from 10 [IX] but not 1 from 20—there is no such number as IXX.)

                For 99, do NOT write IC (C – I or 100 - 1).
                DO write XCIX (XC + IX or 90 + 9)

A bar placed on top of a letter or string of letters increases the numeral's value by 1,000 times.

          XV = 15, (X-bar)(V-bar)= 15,000

One              I     Eleven                    XI     Thirty                   XXX
Two            II     Twelve                  XII     Forty                       XL
Three         III     Thirteen               XIII      Fifty                            L
Four          IV      Fourteen              XIV     Sixty                        LX
Five            V      Fifteen                  XV     Seventy                  LXX
Six            VI      Sixteen                XVI      Eighty                   LXXX
Seven      VII      Seventeen           XVII     Ninety                       XC
Eight       VIII      Eighteen            XVIII     One hundred                C
Nine          IX     Nineteen              XIX      Five hundred                D
Ten             X     Twenty                 XX      One thousand              M

So Simple Yet So Fun

Today we did such a simple craft.  It was something spontaneous and the boys had so much fun making it.  We created a paper chain.  One of the oldest and simplest crafts but it held their attention for almost an hour as we colored and glued the strips of paper.  They enjoyed using their imagination to come up with different ways to color each strip.  Now their finished piece of art is proudly displayed on their bedroom wall.