Adding and subtracting (age 10+)

Question 1

During a school fundraiser, 3,452,786 tickets were sold in the first week. In the second week, 1,128,493 more tickets were sold. After the event, 2,200,000 tickets were found to be invalid and removed from the total count. How many valid tickets were sold in total?

Accepted Answer

2,381,279

Answer

4,581,279

Answer

2,281,279

Answer

3,452,786

Question 2

A community garden earned 3,467,891.75 from spring sales and 1,238,642.50 from summer sales. Afterwards they bought new tools costing 2,500,000.00. Which method should they use to find the money left, and why?

Accepted Answer

Write the numbers in column form and perform the addition and subtraction on paper, because lining up the digits and decimals ensures accuracy with large values.

Answer

Do the whole calculation in your head, because the numbers are round enough to handle mentally.

Answer

Use a calculator to add the two sales amounts, then subtract the cost mentally, because the subtraction is simple.

Answer

Estimate the total sales, then use a calculator for the subtraction, because an estimate is sufficient for the final answer.

Question 3

The town library already has 1,876,543 books. A donor gives the library 2,135,000 more books. After the donation, the library decides to remove 500,000 old books. How many books are in the library now?

Accepted Answer

3,511,543

Answer

4,511,543

Answer

3,011,543

Answer

3,876,543

Try three questions

During a school fundraiser, 3,452,786 tickets were sold in the first week. In the second week, 1,128,493 more tickets were sold. After the event, 2,200,000 tickets were found to be invalid and removed from the total count. How many valid tickets were sold in total?

A community garden earned $3,467,891.75 from spring sales and $1,238,642.50 from summer sales. Afterwards they bought new tools costing $2,500,000.00. Which method should they use to find the money left, and why?

The town library already has 1,876,543 books. A donor gives the library 2,135,000 more books. After the donation, the library decides to remove 500,000 old books. How many books are in the library now?

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