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
- 1.6 + 3 + 9 + 12 + 21 + 33 + 54 + 87 + 141 + 228 =
- 2.Leapfrog list (each number is the sum of the two before it): 1, 2, 3, 5, 8, 13, 21, 34, 55, 89. What is 11 × the 7th number?
- 3.A leapfrog list starts 2, 3 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 4.Leapfrog list (each number is the sum of the two before it): 1, 9, 10, 19, 29, 48, 77, 125, 202, 327. What is 11 × the 7th number?
- 5.4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 + 178 + 288 =
- 6.Leapfrog list (each number is the sum of the two before it): 6, 5, 11, 16, 27, 43, 70, 113, 183, 296. What is 11 × the 7th number?
- 7.9 + 7 + 16 + 23 + 39 + 62 + 101 + 163 + 264 + 427 =
- 8.Leapfrog list (each number is the sum of the two before it): 2, 2, 4, 6, 10, 16, 26, 42, 68, 110. What is 11 × the 7th number?
- 9.Leapfrog list (each number is the sum of the two before it): 5, 5, 10, 15, 25, 40, 65, 105, 170, 275. What is 11 × the 7th number?
- 10.A leapfrog list starts 4, 4 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 11.7 + 6 + 13 + 19 + 32 + 51 + 83 + 134 + 217 + 351 =
- 12.4 + 3 + 7 + 10 + 17 + 27 + 44 + 71 + 115 + 186 =
- 13.4 + 2 + 6 + 8 + 14 + 22 + 36 + 58 + 94 + 152 =
- 14.A leapfrog list starts 1, 3 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 15.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?
- 16.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?
- 17.A leapfrog list starts 3, 5 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 18.A leapfrog list starts 6, 3 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 19.2 + 5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 + 212 =
- 20.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?
- 21.5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 + 212 + 343 =
- 22.9 + 5 + 14 + 19 + 33 + 52 + 85 + 137 + 222 + 359 =
- 23.2 + 4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 + 178 =
- 24.A leapfrog list starts 6, 4 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 25.Leapfrog list (each number is the sum of the two before it): 5, 1, 6, 7, 13, 20, 33, 53, 86, 139. What is 11 × the 7th number?
- 26.7 + 7 + 14 + 21 + 35 + 56 + 91 + 147 + 238 + 385 =
- 27.A leapfrog list starts 9, 1 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 28.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?
- 29.A leapfrog list starts 3, 7 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 30.Leapfrog list (each number is the sum of the two before it): 2, 3, 5, 8, 13, 21, 34, 55, 89, 144. What is 11 × the 7th number?
- 31.2 + 2 + 4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 =
- 32.5 + 1 + 6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 =
- 33.A leapfrog list starts 2, 9 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 34.1 + 5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 + 191 =
- 35.3 + 9 + 12 + 21 + 33 + 54 + 87 + 141 + 228 + 369 =
- 36.A leapfrog list starts 9, 4 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 37.A leapfrog list starts 6, 9 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 38.5 + 3 + 8 + 11 + 19 + 30 + 49 + 79 + 128 + 207 =
- 39.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?
- 40.1 + 6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 + 225 =
Answer key
- 594
- 231
- 374
- 847
- 748
- 770
- 1111
- 286
- 715
- 572
- 913
- 484
- 396
- 319
- 1144
- 946
- 605
- 594
- 550
- 825
- 891
- 935
- 462
- 682
- 363
- 1001
- 583
- 583
- 781
- 374
- 286
- 363
- 902
- 495
- 957
- 847
- 1122
- 539
- 198
- 583
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