Three concepts of subtraction occur in problems, Take away concept, comparison concept, and the missing addend concept.
TAKE AWAY CONCEPT:
an example would be: If you had 20 pencils and you had to give away 10 how many would you have left? -- 20-10=
Answer:10
That's pretty simple!
COMPARISON CONCEPT:
Example: if you had 20 pencils and your friend had 10 pencils. How many more pencils do you have than your friend? 20-10= 10.
Example.
Notice that your still coming up with the same answers with take away concept and the comparison concept. You will also come up with the same answer on the missing addend concept, which is my favorite one!
MISSING ADDEND CONCEPT:
Example: you have 12 kids in a class room and you need a total of 18 students to participate in the activity for it to work. So how many more students are needed to complete the activity? you would do 12+_____=18
your answer would be 6-- 12+6=18. you count up until you reach the number after the equal sign.
Missing Addend example.
Meanings and relationships of the operations.
I like how you explained this subtraction method and gave us links to work with if we did not understand how to do it. Word problems in math are really tough for me and this really helped.
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