A bracket in the equation
Four gift bags are packed alike. Each has some sweets and 3 chocolates. The four bags hold 44 things. Let s be the sweets in one bag. A bracket, as in 4(s + 3), groups what one bag holds. How many sweets are in one bag?
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s + 3: 4(s + 3) = 44.- Four bags, each
s + 3:4(s + 3) = 44. - Way 1: share both sides by 4. Each bag holds 11.
- Take 3 off both sides:
s = 8. - Way 2: multiply 4 into each part of the bracket.
- Take 12 off both sides, then share by 4:
s = 8.
Two ways to work with a bracket
4(s + 3) means four bags. The bracket (s + 3) is one bag. Each bag has s sweets and 3 chocolates.
In Way 1, share both sides by 4. That gives s + 3 = 11, because 44 ÷ 4 = 11. Take 3 off both sides: s = 8, because 11 − 3 = 8.
In Way 2, count the sweets and the chocolates separately. Four bags hold 4s sweets and 12 chocolates, because 4 × 3 = 12. So 4s + 12 = 44. Take 12 off both sides: 4s = 32, because 44 − 12 = 32. Share by 4: s = 8, because 32 ÷ 4 = 8.
Both ways end at 8. Check in the first line: 4 × (8 + 3) = 44.
Rule: Share both sides by the number outside. It cannot be 0. Or multiply it into every part of the bracket. Either way the answer stays.
Watch out!
Multiply the 4 into s alone and 4s + 3 = 44 is a different line. Put 8 in it: 4 × 8 + 3 is 35, not 44.