Solve these calculations using quick mental strategies and estimation tricks.
Don’t include any symbols.

🙂 = Correct, ☹️ = Incorrect

📌 Rules

• Partition numbers into place value parts to make addition and subtraction easier in your head. For example, to add 37 + 46, add the tens first (30 + 40 = 70), then add the ones (7 + 6 = 13), and combine them (70 + 13 = 83).

• Use rounding to check if your answer makes sense before finishing. For example, 123 + 456 is roughly 120 + 460 = 580, so an answer near 579 sounds sensible!

💡 Tips

• Look for near numbers to save time. Adding 29 (like in 73 + 29) is the same as adding 30 and taking away 1 (73 + 30 = 103, then 103 – 1 = 102).

• To multiply by 5 quickly (like in 24 × 5), multiply by 10 first and then halve the answer (24 × 10 = 240, and half of 240 is 120).

• When typing your final answers on our platform, keep typing quick and simple by using plain digits only (for example, write 1000, not 1,000 or 1 000). The answer box handles the rest automatically!

⚠️ Warnings

• Do not forget to adjust back when using rounding! If you round 28 up to 30 to solve 62 – 28 (doing 62 – 30 = 32), you took away 2 extra, so you must add 2 back at the end (32 + 2 = 34 🙂, not 32 ☹️).

• Do not split numbers wrongly when dividing. To solve 648 ÷ 3, split 648 into 600, 40, and 8, or think of it as 600 ÷ 3 = 200, 30 ÷ 3 = 10, and 18 ÷ 3 = 6 to get 216 🙂 (doing 600 ÷ 3 + 48 ÷ 3 also works brilliantly!).