2G add double facts, use 10 to subtract, and addends Lesson

Multiple Choice

Tammy gave 7 markers to Sam. She started with 42 Markers. How many markers does Tammy have now?

• 42 markers

• 47 markers

• 49 markers

• 50 markers

Multiple Choice

What is ten less than 49?

• 59

• 20

• 10

• 39

Find the Unknown Addend

• Use your base 10 blocks or pictures to solve.

• Record your thinking in your student workbook.

• Write the equation.

Multiple Choice

What do you call the numbers being added?

• factors

• addends

• minuend

• subtrahend

Multiple Choice

9+9

• 19

• 50

• 67

• 18

Multiple Choice

44+44

• 88

• 99

• 66

• 77

Double Digit Addition

Use 10 to subtract.

In Kindergarten and 1st grade you learned that TEN AND SOME MORE made a teen number.

You can use that strategy to help you subtract!

Let's go!

- Miss G

In kindergarten or 1st grade you might count by 1s to find out what addend is missing. In 2nd grade we want to just KNOW how much it is!

Now let's use that same fact. 10 + 7 = 17

We know that is true. Which means that 17 - 7 = 10.

BUT WHAT IF THE SUBTRACTION PROBLEM WAS 17 - 9 = ?

No worries! We can use what we know!

Easy! The difference between 7 and 9 is 2. That means we have to subtract 2 more from the fact we already know

Multiple Choice

When you count the ones and get to 10, what do you do next?

• Nothing.

• Put the number of all of the ones in the ones column.

• Circle them up and make a new ten.

• Subtract them.