Math: Estimation and Measurement Flashcards

A map has a scale of 1 inch = 25 miles. Two cities are 3.6 inches apart on the map. What is the actual distance?

Answer: 90 miles

3.6 inches × 25 miles/inch = 90 miles.

A tank is being filled at 2.4 gallons per minute. Approximately how long will it take to fill a 100-gallon tank?

Answer: About 42 minutes

100 ÷ 2.4 ≈ 41.7 minutes, which is approximately 42 minutes.

How many square feet are in 3 square yards?

Answer: 27 sq ft

1 square yard = 9 square feet, so 3 square yards = 27 square feet.

A box weighs 4.72 kilograms. Which is the best estimate rounded to the nearest kilogram?

Answer: 5 kg

4.72 rounded to the nearest whole kilogram is 5 kg, since the tenths digit (7) is ≥ 5.

A student estimates that 12% of 498 is about 60. Is this estimate reasonable?

Answer: Yes, it is reasonable

10% of 500 = 50, and 12% is slightly more, so about 60 is a reasonable estimate.

Which measurement is equivalent to 2.5 kilometers?

Answer: 2,500 meters

1 kilometer = 1,000 meters, so 2.5 km × 1,000 = 2,500 meters.

If a car gets 32 miles per gallon and gas costs $3.89 per gallon, approximately how much does it cost to drive 160 miles?

Answer: About $19

160 ÷ 32 = 5 gallons × $3.89 ≈ $19.45, approximately $19.