Leapfrog Sum Trick Worksheet
The trick (Seventh times eleven): A leapfrog list: start with two numbers, then each number is the sum of the two before it, up to 10 numbers. Find the 7th number. Multiply it by 11 (the number with a 0 on the end, plus the number): that is the total of all 10.
NameDateTime takenScore ___ / 40
- 1.Leapfrog list (each number is the sum of the two before it): 1, 5, 6, 11, 17, 28, 45, 73, 118, 191. What is 11 × the 7th number?
- 2.9 + 7 + 16 + 23 + 39 + 62 + 101 + 163 + 264 + 427 =
- 3.A leapfrog list starts 8, 8 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 4.1 + 6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 + 225 =
- 5.8 + 9 + 17 + 26 + 43 + 69 + 112 + 181 + 293 + 474 =
- 6.9 + 1 + 10 + 11 + 21 + 32 + 53 + 85 + 138 + 223 =
- 7.A leapfrog list starts 5, 1 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 8.5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 + 212 + 343 =
- 9.Leapfrog list (each number is the sum of the two before it): 3, 1, 4, 5, 9, 14, 23, 37, 60, 97. What is 11 × the 7th number?
- 10.9 + 8 + 17 + 25 + 42 + 67 + 109 + 176 + 285 + 461 =
- 11.A leapfrog list starts 5, 4 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 12.A leapfrog list starts 7, 5 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 13.8 + 6 + 14 + 20 + 34 + 54 + 88 + 142 + 230 + 372 =
- 14.7 + 1 + 8 + 9 + 17 + 26 + 43 + 69 + 112 + 181 =
- 15.Leapfrog list (each number is the sum of the two before it): 7, 6, 13, 19, 32, 51, 83, 134, 217, 351. What is 11 × the 7th number?
- 16.A leapfrog list starts 2, 2 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 17.4 + 8 + 12 + 20 + 32 + 52 + 84 + 136 + 220 + 356 =
- 18.A leapfrog list starts 2, 1 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 19.A leapfrog list starts 4, 1 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 20.Leapfrog list (each number is the sum of the two before it): 4, 6, 10, 16, 26, 42, 68, 110, 178, 288. What is 11 × the 7th number?
- 21.A leapfrog list starts 3, 3 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 22.Leapfrog list (each number is the sum of the two before it): 8, 1, 9, 10, 19, 29, 48, 77, 125, 202. What is 11 × the 7th number?
- 23.A leapfrog list starts 6, 7 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 24.A leapfrog list starts 3, 4 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 25.7 + 6 + 13 + 19 + 32 + 51 + 83 + 134 + 217 + 351 =
- 26.5 + 5 + 10 + 15 + 25 + 40 + 65 + 105 + 170 + 275 =
- 27.Leapfrog list (each number is the sum of the two before it): 9, 7, 16, 23, 39, 62, 101, 163, 264, 427. What is 11 × the 7th number?
- 28.Leapfrog list (each number is the sum of the two before it): 6, 8, 14, 22, 36, 58, 94, 152, 246, 398. What is 11 × the 7th number?
- 29.1 + 3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 =
- 30.9 + 6 + 15 + 21 + 36 + 57 + 93 + 150 + 243 + 393 =
- 31.4 + 4 + 8 + 12 + 20 + 32 + 52 + 84 + 136 + 220 =
- 32.6 + 1 + 7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 =
- 33.2 + 5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 + 212 =
- 34.1 + 1 + 2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 =
- 35.2 + 6 + 8 + 14 + 22 + 36 + 58 + 94 + 152 + 246 =
- 36.A leapfrog list starts 9, 6 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 37.2 + 9 + 11 + 20 + 31 + 51 + 82 + 133 + 215 + 348 =
- 38.Leapfrog list (each number is the sum of the two before it): 9, 1, 10, 11, 21, 32, 53, 85, 138, 223. What is 11 × the 7th number?
- 39.A leapfrog list starts 6, 5 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 40.Leapfrog list (each number is the sum of the two before it): 7, 5, 12, 17, 29, 46, 75, 121, 196, 317. What is 11 × the 7th number?
Answer key
- 495
- 1111
- 1144
- 583
- 1232
- 583
- 363
- 891
- 253
- 1199
- 627
- 825
- 968
- 473
- 913
- 286
- 924
- 198
- 308
- 748
- 429
- 528
- 946
- 517
- 913
- 715
- 1111
- 1034
- 319
- 1023
- 572
- 418
- 550
- 143
- 638
- 1023
- 902
- 583
- 770
- 825
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