Chapter 14

We are finishing up Chapter 14:  Mental Math Strategies today and our test will be TOMORROW!  157:  Spanish    158:  English

In this chapter we learned:

     how to add ones mentally by using a doubles fact.  Ex:  7+6=____         6+6=12; 12+1= 13 so, 7+6=13

     how to add mentally by using the 'add the ones' strategy. 

            Ex:  23+4=___             23 becomes 20 and 3.  Add the ones:  3+4= 7.  Add the ones to the tens:  20+7= 27

     how to add mentally by using the 'add the tens' strategy.

             Ex:  15+20=____          15 becomes 10 and 5.  Add the tens:  10+20= 30.  Add the tens to the ones:  5+30= 35

     how to subtract ones mentally by recalling number bonds (think of addition).  Ex:  8-5=_____           8= 5+ ____         8=5+3 so, 8-5= 3

     how to subtract mentally by using 'subtract the ones' strategy.

              Ex:  37-4=________            37 becomes 30 and 7.  Subtract the ones:  7-4= 3.  Add the ones to the tens:  30+3= 33.  So, 37-4= 33

     how to subtract mentally by using 'subtract the tens' strategy.

               Ex:  35-20= ______              35 becomes 30 and 5.  Subtact the tens:  30-20= 10.  Add the tens to the ones:  10+5= 15.  So, 35-20= 15

     word problems using addition or subtraction:  I have 16 fish.  9 of them swam away.  How many fish are left?  

It is important to keep in mind that your child was introduced to each of these strategies, but we encourage each student to use the strategy that works for them.  They are not required to use all of these strategies, just one!

Our next chapter is 16:  Numbers to 100