# subtraction

• May 9th 2008, 08:25 AM
recca
subtraction
Tylishia says that she can solve 324-197 by adding 3 to both numbers and solving 327-200 instead

a draw a number line (which needs not be perfectly to scale) to help you explain why Tylishia's method is valid.

b. Explain in another way why Tylishia's method is valid.

C. Could you adapt Tylishia's method to other subtraction problems, such as to the problem 183-49? If so, give at least two more examples and show how to apply Tylishia's method in each case.

Thank you
• May 9th 2008, 08:33 AM
Moo
Quote:

Originally Posted by recca
Tylishia says that she can solve 324-197 by adding 3 to both numbers and solving 327-200 instead

a draw a number line (which needs not be perfectly to scale) to help you explain why Tylishia's method is valid.

b. Explain in another way why Tylishia's method is valid.

C. Could you adapt Tylishia's method to other subtraction problems, such as to the problem 183-49? If so, give at least two more examples and show how to apply Tylishia's method in each case.

Thank you

Hello,

For the first one :

Attachment 6254

What can you conclude ?

For the second one :

What does it mean "add 3 to each number" ?

What you're asked is if (324+3)-(197+3)=324-197
Study the LHS by removing the parenthesis (and don't forget the - sign)
• May 9th 2008, 09:49 AM
recca
Help
I do not understand
• May 9th 2008, 10:05 AM
Moo
You can see on the line that the distance between 324 and 197 is the same as 327 and 200.
So the difference is equal.

Question 2. :

(324+3)-(197+3)=324+3-197-3=324-197+3-3=324-197