209 228 247 266 285 304 323 342 361 380 399
19.
20,25,30,35,40,45
20, 25, 30, 35, 40, 45.
The answer depends on what tables you know. For a very naive user: 220 * 19 = (200 + 20)*(20 - 1) = 200*20 - 200*1 + 20*20 - 20*1 = 4000 - 200 + 400 - 20 = 4180 For more proficient users: 220 * (20 - 1) = 220*20 - 220*1 = 4400 - 220 = 4180 or (200 + 20)*19 = 200*19 + 20*19 = 3800 + 380 = 4180
19
19.
Positive integer multiples of 23 which lie between 400 and 499 are: 23 x 18 = 414 23 x 19 = 437 23 x 20 = 460 23 x 21 = 483
20,25,30,35,40,45
Multiples of 7: 7, 14, 21, 28, 35,... Multiples of 19: 19, 38, 57, 76, 95,...
They are: 21, 28, 35, 42 and 49
20, 25, 30, 35, 40, 45.
The answer depends on what tables you know. For a very naive user: 220 * 19 = (200 + 20)*(20 - 1) = 200*20 - 200*1 + 20*20 - 20*1 = 4000 - 200 + 400 - 20 = 4180 For more proficient users: 220 * (20 - 1) = 220*20 - 220*1 = 4400 - 220 = 4180 or (200 + 20)*19 = 200*19 + 20*19 = 3800 + 380 = 4180
There are no integer multiples of 7 between 135 and 139: 19 x 7 = 133, while 20 x 7 = 140.
19
400 multiplied by 19 is 7,600.
20, 25, 30, 35, 40, 45, 50, 55.
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