Basic Math Concepts Mrs Trippodo Public School 100

Basic Math Concepts Mrs. Trippodo Public School 100 First Grade Addition & Subtraction

Addition § Addition is taking two smaller groups and putting them together to make a larger group.

The Plus Sign § The plus sign is used to show addition. § The plus sign looks like this: + § It goes between the two numbers being added: ____ + _____

The Equal Sign § The equal sign goes at the end of the number sentence right before the sum or answer. § The equal sign looks like this: = § _____ + _____ = ______(sum)

How Many Altogether? § Altogether is an important word in addition § Let’s try an example § There are 2 apples in a basket. 3 more apples are put into the basket. § How many apples are in the basket altogether? Count §Add 2 + 3 = 5 There are 5 apples altogether. The sum is 5.

§ Let’s try another example § You have 4 toys § Your friend gives you 3 more § How many toys do you have altogether? § Count § Add: 4 + 3 = 7 There are 7 toys altogether. The sum is 7.

Subtraction § Subtraction is the opposite of addition. § In subtraction, you start with a large group and “take away” to make the group smaller.

The Minus Sign § The minus sign is used to show subtraction. § The minus sign looks like this: § It means to take away § It goes before the number being subtracted: _____ - _____

The Equal Sign § Same as addition, the equal sign goes at the end of the number sentence. In subtraction the answer is called the difference. § The equal sign looks like this: = § _____ - _____ = ______(difference)

How Many Are Left? § There are 5 slices of pizza. § You are hungry and eat 2 slices. § How many slices are left? Count § Subtract: 5 – 2 = 3 There are 3 slices of pizza left. § The difference is 3.

§ Let’s try another example § You have 4 keys § You give your friend 2 keys. § How many keys do you have left? § Count § Subtract: 4 – 2 = 2 There are 2 keys left. § The difference is 2.

Basic Operations § We learned about two basic operations: § Addition and Subtraction § When we need to know how many altogether, we use Addition When we take away and need to know how many are left, we use Subtraction

Summary Slide § Addition § The Plus Sign § The Equal Sign § How Many Altogether?

Summary Slide § Subtraction § § § The Minus Sign The Equal Sign How Many Are Left?

If you have any questions, please ask.