Math Drills
Finding the Base Quantity
A-2Word Problems (Decimals, %)
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What this worksheet covers
- Topic
- Percentage
- Worksheet
- Finding the Base Quantity
The compared amount is divided by its percentage to trace back to the base amount. The percentage is shown as a decimal, as a percent, or as wari, and the wari questions restate it as a decimal before dividing. Where a question says an amount grew or shrank from the original, the word problems divide by 1 plus or 1 minus that percentage.
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A percent question needs one step before the dividing, turning the percent into a decimal. Divide by 40 with 40% left as it stands and the answer comes out a hundredth of the true figure, two places too small. What to multiply back by is the percentage itself in a basic question, or 1 with the percentage added or taken away in an increase or decrease question, and either returns the compared amount.
Of the three types, the direction that traces backward by dividing is complete here. From the next lesson a drawing expressing that percentage as a length or an angle gets read. The amount produced by multiplying in Finding the Compared Quantity has been moved here into the clues.
- Decimals (Basics)2 questions
- % (Basics)2 questions
- Decimals (Applying Increase and Decrease)1 question
- % (Applications)1 question
Questions & answers
Problems and answers on this worksheet
These are the problems in “Percentage”, shown with their answers.
(1)A height equal to 0.5 of the height of a tree is 8m. What is the total height of the tree in how many m? Answer □
Answer: 16m
(2)A length equal to 0.4 of the perimeter of a pond is 36m. What is the total length around the pond in how many m? Answer □
Answer: 90m
(3)The number of boys in a class is 20, which is 25% of the whole class. How many students are in the whole class in total? Answer □
Answer: 80students
(4)The number of books returned to the library today is 17, which is 85% of all the checked-out books. How many books are checked out in all? Answer □
Answer: 20books
(5)This year, the amount harvested at a farm was 720 kg, which is less than last year by a ratio of 0.25. How many kg were harvested last year? Answer □
Answer: 960kg
(6)The milk production of a ranch this year is 660L, which is 10% more than last year. How many L was the production last year? Answer □
Answer: 600L
What to do next
More worksheets in this unit
Finding the PercentageFinding the Percentage Word Problems (Decimals, Basic)
Finding the PercentageFinding the Percentage Word Problems (%, Application)
Finding the Compared QuantityFinding the Compared Quantity Word Problems (Basic)
Finding the Compared QuantityFinding the Compared Quantity Word Problems (Increase/Decrease, 2 Steps)
