Estimate differences up to 1,000

Learning Objectives Round 3-digit numbers to the nearest ten. Round 3-digit numbers to the nearest hundred. Use rounded numbers to estimate the difference between two numbers up to 1,000. Solve word problems that require estimating differences. Explain why an estimated answer is reasonable. Compare an estimated difference to the actual difference. You have 525 tickets at the arcade and a prize costs 289 tickets. About how many tickets will you have left? 🤔 In this lesson, we will learn a super-fast math trick called 'estimating' to find answers that are close to the real answer. Estimating differences helps you make quick guesses and check if your subtraction work is correct. Real-World Applications Figuring out about how much money you'll have left afte...

TermDefinitionExample EstimateA close guess to the actual answer. It's not exact, but it's nearby.An estimate for 198 - 103 is 200 - 100 = 100. DifferenceThe answer you get when you subtract one number from another.The difference between 15 and 6 is 9. RoundingMaking a number simpler by finding the closest ten or hundred. It makes math easier!Rounding 48 to the nearest ten gives you 50. AboutA word we use when we are estimating. It means 'close to' or 'nearly'.87 - 29 is about 60. Nearest TenThe ten that a number is closest to on a number line (like 10, 20, 30...).The nearest ten to 173 is 170. Nearest HundredThe hundred that a number is closest to on a number line (like 100, 200, 300...).The nearest hundred to 624 is 600.

The '5 or More' Rule for Tens Look at the ones digit. If it's 5, 6, 7, 8, or 9, round up to the next ten. If it's 0, 1, 2, 3, or 4, round down. Use this rule to make a number end in a zero. This makes it easier to subtract in your head. The '50 or More' Rule for Hundreds Look at the tens digit. If it's 5, 6, 7, 8, or 9, round up to the next hundred. If it's 0, 1, 2, 3, or 4, round down. Use this rule for bigger numbers to make them end in two zeros. This is great for very quick estimates. The Estimation Subtraction Formula Actual Difference \approx Rounded Number 1 - Rounded Number 2 To estimate a difference, first round the numbers you are subtracting, and then subtract the rounded numbers.