Multiplying 2 digit numbers where the tens’ digit is the same and the units’ digit add up to 10
E.g.: 42 x 48
1. First multiply the units digit of the two numbers: 2 x 8 = 16
2. Then multiply the tens digit by its succeeding number, 4x(4+1) = 4x5 = 20.
3. The final answer is 2016.
Multiplying 2 digit numbers where the tens’ digit numbers add up to 10 and the units’ digit is the same
E.g.: 44 x 64
1. First find the multiplication of the last 2 digits of both the numbers i.e. 4x4 = 16
2. Multiply the tens’ digits and add the common digit to the multiplication i.e. (4x6)+4 = 28
Now try to solve these 10 questions as fast as possible (3-5min)
1. 74 x 76=?
(a) 4924 (b) 5624 (c) 5424 (d) 5024
2. 41 x 49=?
(a) 1909 (b) 2081 (c) 2009 (d) 2109
3. 81 x 89=?
(a) 8109 (b) 8181 (c) 7281 (d) 7209
4. 65 x 65 =?
(a) 4225 (b) 4275 (c) 3625 (d) 3675
5. 29 x 21=?
(a) 409 (b) 609 (c) 481 (d) 681
6. 45 x 65=?
(a) 2975 (b) 2925 (c) 2425 (d) 3025
7. 28 x 88 =?
(a) 2664 (b) 2648 (c) 2464 (d) 2848
8. 33 x 73=?
(a) 2109 (b) 2437 (c) 2327 (d) 2409
9. 81 x 21 =?
(a) 1701 (b) 1601 (c) 1621 (d) 1721
10. 67 x 47=?
(a) 3049 (b) 3149 (c) 2407 (d) 2449
SOLUTIONS
1 b 2 c 3 d 4 a 5 b
6 b 7 c 8 d 9 a 10 b
Within 3 min: Excellent
3-5 min: You Can Do Better
More than 5 min: You Need To Work Hard.
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