Tuesday

Addition and Subtraction Number Sentences

Sometimes, additions are written with blanks in them:

E.g.  __ + 5 = 10

What is __?

Have a guess. Now put the number you guessed into the blank. Did the sentence work? Did you use your doubles to help you?
That might be too easy for some of you. What about 50 = __ + 32?
Or 80 + 38 = 85 + ___.


Let's start with the basics:







Practice this skill using these activities:
- Try creating all the different additions that equal 20. E.g. 5 + 15, 6 + 14 and continue.


Remember: Like in the video, if you flip the numbers around it will still equal 20, E.g. 6  + 14 is the same as 14 + 6. Or 20 = 14 + 6 AND that's the same as 20 = 6 + 14.

Careful: 4 +16 is not the same as 20 + 4! Watch this video to learn more.



Now try all the subtractions from 20, e.g.:
20 - 14 = 6
20 - 6 = 14
Keep going!  

- Now try to come up with all the combinations that make 50. Then all the subtraction from 50.

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