Subtraction Problems With Decimals

 

WALT: Solve subtraction problems with tenths by changing the second number into a whole number.

Success Criteria: I will

• Round the second number to a tidy whole number.
• Any changes I make to one addend I have to make to the other because the distance between the two numbers must remain the same.

HERE IS EVIDENCE OF MY WORK THAT I HAVE DONE:

HERE IS A VIDEO OF ME SHOWING HOW TO USE THIS STRATEGY:

My Reflection:

A question I wanted to know was why do you have to make sure that it balances?  When you subtract or add from one addend you have to do the same to the other.  Addition problems are different.  I didn't realise until I was shown that the distance or difference between the two numbers have to stay the same.

I also discovered that it was easier to subtract when the second number was a whole amount.

This strategy is easy once you practice it a few times.  I wonder if it will still be easier when you are subtracting hundredths and thousandths? Lucky I don't have to worry about that until next year.