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May 2012

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The ideas in this addition lesson are taken from Add & Subtract 2-B ebook. Only a few examples of each problem type are shown; you should make more problems of each kind for the student.

Adding without going to the next ten
Free lesson plan from Homeschool Math.net

Remember how numbers are broken down into TENS and ONES: 

= + 23 = 20 + 3

= + 47 = 40 + 7

Break down these numbers into their tens part and ones part.

We can do this the other way around!  Add with whole tens.

Now look carefully at these additions.

+    =  =  12 + 3 = 10 + 2 + 3  = 15

+    =   =  25 + 3  = 20 + 5 + 3  = 28

+    =  =  34  + 4  = 30 + 4 + 4 = 38

The amount of tens does not change!

Example problem types

Example problem types

1.  In a similar way, add the following numbers.  The tens are already shown in the answer picture.  Draw more little dots to show the complete answer.  

+       =          33  +  4 =	+       =   16  +  3  =
+       =    21  +  6 =	+       =

2.  Add.  Compare the problems.

3.  Add.  For each problem, write a corresponding problem with just the ones' digits.

  
4.  Find the missing addend.

5. Find the pattern and continue it!

stands for a mystery number between 1 and 100.  See if you can compare the expressions without knowing the mystery number! There is one comparison you cannot do without knowing the mystery number. Write < or > in the box between the expressions. + 5     + 4        5    4       5            + 2   + 7 5   6 +   + 20       + 10     + 30 2     10 +

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