CECmath.35


TITLE:    EASY ADDITION

AUTHOR:   Lauren Evans, Su-Valley Junior/Senior High
          School, Talkeetna, Alaska

GRADE LEVEL:   MATH  4-12  (I teach it to 7-8)

OVERVIEW:
Students are having trouble with CARRYING in ADDITION
problems or:
     students are slow when adding
     students want to add faster and more accurately
     students want to add without pencil and paper

PURPOSE:
This gives kids an alternative way of adding if they
have trouble with 'carrying'.  It is also faster and
more accurate for MOST kids.

I have all of the kids try this then ENCOURAGE the ones
that have trouble with addition to use it all of the
time.

The biggest problem is that a few kids think it is sort
of cheating to use this method because it doesn't
follow the 'rules' of addition.  Once convinced it is
OKAY to use, they like it.

This also works for multiplying, but that's another
lesson.

OBJECTIVES:  Upon completion of this lesson, the
student will be able to add correctly and quickly.

RESOURCES/MATERIALS:  Paper, pencil, addition problems.

ACTIVITIES (here's the lesson):
     1) problem -         35
                        + 24
                         ----
     2)  Add from LEFT TO RIGHT (the OLD way is to
         add the ONES first and then carry)

         Add the TENS first    30
                             + 20
                             ------
                               50

         Then add the ONES      5
                             +  4
                              -----
                                9

         Then add the answers  50
                             +  9
                              ----
                               59    NO CARRYING
TIP  *  Start with problems that require NO carrying
(when using the OLD method) so they get the idea...
progress to tougher problems (below).

          steps        (1)     (2)   (3)
EXAMPLES:     378      300     70     8
            + 958    + 900   + 50   + 8
            ------   ------   ----   ---
             1200 <-- 1200
      (4)     120 <---------  120
    (add)      16 <----------------  16
           ------
             1336     THE ANSWER!!!

    steps         (1)       (2)    (3)   (4)     (5)
EXAMPLE:  5830             5000    800     30     0
          2967             2000    900     60     7
           836                     800     30     6
       + 38566  + 30000  + 8000  + 500   + 60    + 6
      --------   -------  ------  -----   ----   ---
         30000 <-  30000
         15000 <-----------15000
    (6)   3000 <------------------ 3000
    add    180 <---------------------------180
            19*<----------------------------------19
        --------
         48199     THE ANSWER!!!

TIP:  If the above example had a list of sums that
ended with a 20 *(rather than 19), the list can be
added just as the original problem was added so that
the student won't have to carry here either.  See the
sample below.

EXAMPLE:
           5830
           2967
            836
       +  38567
       --------
          30000
          15000
           3000
            180     Here the 80 + 20 = 100.  Using
             20     the old method of adding, the
         -------    '1' would have to be carried...
          40000     here we just add from left to
           8000     right again to get rid of that
            100     problem...
            100
        -------
          48200     THE ANSWER!!!

TYING IT TOGETHER:
Do math problems and test the kids for speed and
accuracy.  I usually do a pretest without telling the
kids why...having them time the test.  I keep this and
give it again a couple/three weeks later once they know
the new method.  They seldom are less accurate or take
more time.