Lesson · Grade 7 · Mathematics
Writing an equation from a word problem
- Grade 7
- Mathematics
- 1 min 7 s
- British Columbia
- BC7-MA-45
A story about 3 packs of stickers and 5 loose stickers making 26 is turned into an equation one phrase at a time: x is the number in one pack, 3 packs make 3x, the 5 loose stickers add 5, and 26 in all is what it equals, so 3x + 5 = 26, while a picture of the packs and stickers shows the same story. The equation is then solved by subtracting 5 and dividing by 3 to give 7 stickers in each pack, checked with 3 × 7 + 5 = 26, and the video ends on the recap: name the unknown, write the equation, solve.
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In one sentence
The question this lesson answers
Ana has 3 packs of stickers and 5 loose stickers, which makes 26 stickers in all.
How many stickers are in one pack?
Transcript
What the lesson says
Ana has 3 packs of stickers and 5 loose stickers, which makes 26 stickers in all.
How many stickers are in one pack?
We do not know that number yet, so we call it x.
Each pack has x stickers, so 3 packs have 3x stickers.
And means add, so the 5 loose stickers give plus 5.
In all means the total, so everything together equals 26.
So the equation is 3x plus 5 equals 26.
To solve it, subtract 5 from both sides, so 3x equals 21.
Then divide both sides by 3, so x equals 7.
So there are 7 stickers in each pack.
Check it: 3 times 7 is 21, and 21 plus 5 is 26.
Name the unknown, turn the story into an equation, then solve it.
Curriculum
Where this fits
- British Columbia, Grade 7
Mathematics, Patterns and algebra: two-step equations with whole-number coefficients, constants, and solutionsBC7-MA-45
The outcomes and strands follow the British Columbia curriculum.
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