Mental Maths

Mental maths shortcuts turn long multiplications into quick steps. They come from simple algebra and number facts that are easy to learn.

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1. Q1Medium

   25 × 108 = ?

   1. A3,100
   2. B2,710
   3. C2,725
   4. D2,700
   Show answer

   Answer: D. 2,700

   💡 25 = 100 ÷ 4, so 108 × 100 ÷ 4 = 2,700.

2. Q2Medium

   11 × 26 = ?

   1. A276
   2. B268
   3. C386
   4. D286
   Show answer

   Answer: D. 286

   💡 Put 2 + 6 = 8 between the digits: 286.

3. Q3Medium

   25 × 28 = ?

   1. A574
   2. B70
   3. C725
   4. D700
   Show answer

   Answer: D. 700

   💡 25 = 100 ÷ 4, so 28 × 100 ÷ 4 = 700.

4. Q4Medium

   25 × 96 = ?

   1. A1,968
   2. B240
   3. C2,400
   4. D2,375
   Show answer

   Answer: C. 2,400

   💡 25 = 100 ÷ 4, so 96 × 100 ÷ 4 = 2,400.

5. Q5Hard

   89 × 91 = ?

   1. A8,099
   2. B8,089
   3. C7,699
   4. D7,799
   Show answer

   Answer: A. 8,099

   💡 (90 − 1)(90 + 1) = 90² − 1² = 8,099.

6. Q6Hard

   87 × 93 = ?

   1. A8,291
   2. B8,101
   3. C8,091
   4. D8,109
   Show answer

   Answer: C. 8,091

   💡 (90 − 3)(90 + 3) = 90² − 3² = 8,091.

7. Q7Hard

   45² = ?

   1. A2,227
   2. B2,005
   3. C2,125
   4. D2,025
   Show answer

   Answer: D. 2,025

   💡 4 × 5 = 20, then write 25: 2,025.

8. Q8Hard

   69 × 71 = ?

   1. A4,889
   2. B4,899
   3. C4,699
   4. D3,920
   Show answer

   Answer: B. 4,899

   💡 (70 − 1)(70 + 1) = 70² − 1² = 4,899.