Write a story problem for the addition sentence 7+__=9. solve the story problem.

Story:

Karina had 7 notebooks. He sister left for her some more notebooks, but Karina did not check how many.

Later she counted, and she had 9 notebooks.

How many notebooks did her sister leave for her?

and the solution:

7+x=9

we subtract 7 from both sides:

7-7+x=9-7

now we calculate what we can:

x=2

so the solution is: she left two notebooks.

Ithink this answer would be c cause i seen this before