Lesson: Subtracting by Adding with Numbers up to 20 Mathematics • 1st Grade
In this lesson, we will learn how to solve subtraction problems by finding the missing part in an addition expression with numbers up to 20.
Sample Question Videos
Matthew had 17 toy cars.
He lost 6 of the cars.
He can work out how many cars are left by completing either number sentence:
How many cars are left?
Isabella built 13 sandcastles on the beach. The tide came in and washed some of them away. There are 7 left and she wants to know how many were washed away.
Which of these number sentences does she need to solve?
Which of these addition facts can help her to solve the problem?
How many sandcastles were washed away?
Hint: Use to solve .
Hannah and Anthony made 19 cupcakes.
After their dog ate some, there were 15 left.
They want to know how many cakes their dog ate.
Who is correct?