Algebra notes

Is your child having trouble on the algebra questions on the last page of the study guide?  Take a look here for some help: 

Algebra:

Pictures/shapes stand for something we don’t know.  Use a related fact (fact family) to solve.  

Example:  ∆  + 3 = 5  What is ∆ ?  Well if we know something plus 3 = 5, then 5-3 would tell us the answer is 2.  Check it-2+3=5 J

∆  + 8 = 16  What is ∆ ?

∆  - 6  = 4  What is ∆ ?

∆  + 7 = 10  What is ∆ ?

∆  + 3 = 15  What is ∆ ?

Now try this…

∆  + ∆ = 10  What is ∆ ?  Well, we are adding two of the same number.  So what number added twice = 10?  5+5 = 10 J

Your turn:

If  ∆  +  ∆  = 20, then  ∆ = _____

If  ∆  +  ∆  = 8, then  ∆ = _____

If  ∆  +  ∆  = 16, then  ∆ = _____

If  ∆  +  ∆  = 100, then  ∆ = _____

OK….now let’s try this.  Use the answer from the first problem to solve the next two.  If  ∆  +  ∆  = 8, then  ∆ = _____.  Plug your answer into the spot where the triangles are.  And  ∆ + 9 = ____________,  And   19 - ∆ = _________.

So 4 + 4 = 8, ∆ = 4.  Then plug in 4 for the next problems:  4+9=13 and 19-4=15

Now you try: 

If  ∆  +  ∆  = 10, then  ∆ = _____

And  ∆ + 20 = ____________,

And   30 - ∆ = _________.

If  ∆  +  ∆  = 14, then  ∆ = _____

And  ∆ + 5 = ____________,

And   10 - ∆ = _________.