Math Examples

When subtracting, try keeping the first number whole and subtract the second number in parts. 
Example: 184 - 64 =

184 - 4 = 180
180 - 60 = 120 

 Another example:  274 - 159 =

274 - 100 = 174
174 - 50 = 124
124 - 4 = 120
120 - 5 = 115
 Notice I started with the first number, 274 and kept it whole.  Then I subtracted 159 in parts, which is shown in blue.  There are other ways to break the number up and the "chunks" can be subtracted in any order.  However it makes sense to you!!
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36 + 26 =

There are two strategies to solve this problem.  The first one is called "10s and 1s"  You start by adding the 10s from each number.  Next, you add the 1s from each number.  Then you add the 10s and 1s together.  All steps need to be recorded as shown below.

30 + 20 = 50

6 + 6 = 12

50 + 12 = 62

Ok, now for the second strategy.  This one is called "keep one number whole".  Some students say that they "figure it out in their head".  They might be using this strategy mentally, and just need to learn how to record it.  You start with one of the numbers.  Then you add the other number on in parts as shown below.

  36 + 20 = 56

56 + 6 = 62

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Now, what if you want to find out how far 62 is from 100.  There are two ways to do this-
ADD UP

62 + 8 = 70
70 + 10 = 80 
80 + 10 = 90
90 + 10 = 100


8 + 10 + 10 + 10 = 38


SUBTRACT BACK


100 - 10 = 90
90 - 10 = 80 
80 - 10 = 70
70 - 8 = 62


10 + 10 + 10 + 8 = 38


Both ways can be done on a number line and most of the kids prefer showing it on a number line.