Math: Number Sense and Operations Flashcards

A retail item is originally priced at $80.00. It is first discounted by 20%, and then a coupon is applied for an additional 10% off the discounted price. What is the final price of the item?

Answer: $57.60

First, calculate the initial 20% discount: $80.00 * 0.20 = $16.00. The sale price is $80.00 - $16.00 = $64.00. Next, calculate the additional 10% coupon on the sale price: $64.00 * 0.10 = $6.40. The final price is $64.00 - $6.40 = $57.60.

Which of the following lists correctly orders the numbers from least to greatest?

Answer: 0.35, 3/8, 38%, 2/5

To compare the numbers, convert them all to decimals: 3/8 = 0.375, 0.35 remains 0.35, 38% = 0.38, and 2/5 = 0.40. Ordering these decimals from least to greatest gives 0.35, 0.375, 0.38, 0.40, which corresponds to the original numbers in the order 0.35, 3/8, 38%, 2/5.

What is the value of the expression 5 + 3 * (12 - 4 * 2)² ?

Answer: 53

Following the order of operations (PEMDAS/BODMAS): First, solve inside the Parentheses: 4 * 2 = 8, then 12 - 8 = 4. Next, handle the Exponent: 4² = 16. Then, perform the Multiplication: 3 * 16 = 48. Finally, do the Addition: 5 + 48 = 53.

A map has a scale where 1.5 inches represents 40 miles. If the distance between two cities on the map is 5.25 inches, what is the actual distance between the cities in miles?

Answer: 140 miles

This can be solved by setting up a proportion: (1.5 inches / 40 miles) = (5.25 inches / x miles). Cross-multiply to solve for x: 1.5 * x = 5.25 * 40. This gives 1.5x = 210. Dividing both sides by 1.5 yields x = 140 miles.

The diameter of a specific virus is approximately 0.00000008 meters. How would this number be expressed in scientific notation?

Answer: 8 x 10⁻⁸ m

To write 0.00000008 in scientific notation, move the decimal point to the right until there is one non-zero digit to its left. In this case, the decimal moves 8 places to the right to get '8'. Because the original number is less than 1, the exponent is negative. Therefore, the correct notation is 8 x 10⁻⁸ m.

Which of the following is a prime number?

Answer: 73

A prime number is a whole number greater than 1 with only two divisors: 1 and itself. We can test the options: 87 is divisible by 3 (8+7=15), 51 is divisible by 3 (5+1=6), and 91 is divisible by 7 (7 x 13). The number 73 has no other divisors besides 1 and 73, making it the prime number.