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
- 1.2 + 7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 + 280 =
- 2.4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 + 199 + 322 =
- 3.A leapfrog list starts 4, 2 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 4.8 + 9 + 17 + 26 + 43 + 69 + 112 + 181 + 293 + 474 =
- 5.4 + 4 + 8 + 12 + 20 + 32 + 52 + 84 + 136 + 220 =
- 6.A leapfrog list starts 3, 1 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 7.5 + 2 + 7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 =
- 8.2 + 6 + 8 + 14 + 22 + 36 + 58 + 94 + 152 + 246 =
- 9.Leapfrog list (each number is the sum of the two before it): 7, 4, 11, 15, 26, 41, 67, 108, 175, 283. What is 11 × the 7th number?
- 10.Leapfrog list (each number is the sum of the two before it): 4, 2, 6, 8, 14, 22, 36, 58, 94, 152. What is 11 × the 7th number?
- 11.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?
- 12.5 + 5 + 10 + 15 + 25 + 40 + 65 + 105 + 170 + 275 =
- 13.A leapfrog list starts 4, 3 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 14.A leapfrog list starts 9, 8 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 15.4 + 8 + 12 + 20 + 32 + 52 + 84 + 136 + 220 + 356 =
- 16.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?
- 17.2 + 5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 + 212 =
- 18.6 + 4 + 10 + 14 + 24 + 38 + 62 + 100 + 162 + 262 =
- 19.A leapfrog list starts 9, 3 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 20.4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 + 254 =
- 21.5 + 1 + 6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 =
- 22.7 + 1 + 8 + 9 + 17 + 26 + 43 + 69 + 112 + 181 =
- 23.Leapfrog list (each number is the sum of the two before it): 4, 7, 11, 18, 29, 47, 76, 123, 199, 322. What is 11 × the 7th number?
- 24.9 + 9 + 18 + 27 + 45 + 72 + 117 + 189 + 306 + 495 =
- 25.Leapfrog list (each number is the sum of the two before it): 1, 8, 9, 17, 26, 43, 69, 112, 181, 293. What is 11 × the 7th number?
- 26.Leapfrog list (each number is the sum of the two before it): 3, 9, 12, 21, 33, 54, 87, 141, 228, 369. What is 11 × the 7th number?
- 27.5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 + 254 + 411 =
- 28.A leapfrog list starts 7, 8 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 29.Leapfrog list (each number is the sum of the two before it): 5, 2, 7, 9, 16, 25, 41, 66, 107, 173. What is 11 × the 7th number?
- 30.Leapfrog list (each number is the sum of the two before it): 1, 4, 5, 9, 14, 23, 37, 60, 97, 157. What is 11 × the 7th number?
- 31.Leapfrog list (each number is the sum of the two before it): 3, 6, 9, 15, 24, 39, 63, 102, 165, 267. What is 11 × the 7th number?
- 32.A leapfrog list starts 7, 6 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 33.A leapfrog list starts 5, 5 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 34.A leapfrog list starts 8, 4 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 35.A leapfrog list starts 6, 8 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 36.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?
- 37.7 + 2 + 9 + 11 + 20 + 31 + 51 + 82 + 133 + 215 =
- 38.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?
- 39.3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 + 199 =
- 40.1 + 2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 =
Answer key
- 726
- 836
- 396
- 1232
- 572
- 253
- 451
- 638
- 737
- 396
- 374
- 715
- 484
- 1199
- 924
- 1023
- 550
- 682
- 759
- 660
- 363
- 473
- 836
- 1287
- 759
- 957
- 1067
- 1089
- 451
- 407
- 693
- 913
- 715
- 792
- 1034
- 946
- 561
- 781
- 517
- 231
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