Lesson: Relating Addition to Subtraction: Numbers up to 20 Mathematics • 1st Grade
In this lesson, we will learn how to write a family of addition and subtraction facts linking three numbers up to 20.
We know that 8 plus 7 is 15. Here are the four number sentences for 8, 7, and 15.
Here are some number sentences for 5, 6, and 11. Which number sentence for 5, 6, and 11, is missing?
Which number sentence is wrong?
16 plus 3 is 19. Which number sentence is missing from the number sentences