Addition & Subtraction Flashcards

All 5 cards in this deck

What are the steps to add two decimals using column addition?

e.g. $3.4 + 12.75$

1. Line up the decimal points, filling gaps with zeros: $03.40 + 12.75$
2. Add each column from the right, carrying over
3. Keep the decimal point in line: $16.15$

True or false? To add decimals in columns you line up the last digits on the right.

False. You line up the decimal points, so that digits of the same place value are together.

What is the inverse operation of addition?

Subtraction.
e.g. $7 + 5 = 12$ so $12 - 5 = 7$

How can you check the answer to a subtraction?

Add the answer to the number subtracted; you should get the starting number.
e.g. $9 - 4 = 5$, check $5 + 4 = 9$

When subtracting decimals in a column, what do you do if the top number has fewer decimal places?

e.g. $5.2 - 3.65$

Fill the empty places with zeros: $5.20 - 3.65$