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.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?
- 2.2 + 5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 + 212 =
- 3.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?
- 4.9 + 8 + 17 + 25 + 42 + 67 + 109 + 176 + 285 + 461 =
- 5.A leapfrog list starts 2, 7 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 6.4 + 2 + 6 + 8 + 14 + 22 + 36 + 58 + 94 + 152 =
- 7.5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 + 254 + 411 =
- 8.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?
- 9.A leapfrog list starts 7, 2 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 10.7 + 1 + 8 + 9 + 17 + 26 + 43 + 69 + 112 + 181 =
- 11.Leapfrog list (each number is the sum of the two before it): 4, 5, 9, 14, 23, 37, 60, 97, 157, 254. What is 11 × the 7th number?
- 12.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?
- 13.Leapfrog list (each number is the sum of the two before it): 3, 2, 5, 7, 12, 19, 31, 50, 81, 131. What is 11 × the 7th number?
- 14.4 + 9 + 13 + 22 + 35 + 57 + 92 + 149 + 241 + 390 =
- 15.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?
- 16.2 + 9 + 11 + 20 + 31 + 51 + 82 + 133 + 215 + 348 =
- 17.5 + 2 + 7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 =
- 18.5 + 4 + 9 + 13 + 22 + 35 + 57 + 92 + 149 + 241 =
- 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.Leapfrog list (each number is the sum of the two before it): 6, 1, 7, 8, 15, 23, 38, 61, 99, 160. What is 11 × the 7th number?
- 21.A leapfrog list starts 5, 8 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 22.A leapfrog list starts 5, 3 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 23.5 + 1 + 6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 =
- 24.A leapfrog list starts 8, 6 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 25.3 + 9 + 12 + 21 + 33 + 54 + 87 + 141 + 228 + 369 =
- 26.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?
- 27.Leapfrog list (each number is the sum of the two before it): 9, 6, 15, 21, 36, 57, 93, 150, 243, 393. What is 11 × the 7th number?
- 28.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?
- 29.1 + 6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 + 225 =
- 30.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?
- 31.4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 + 199 + 322 =
- 32.A leapfrog list starts 7, 4 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 33.Leapfrog list (each number is the sum of the two before it): 8, 7, 15, 22, 37, 59, 96, 155, 251, 406. What is 11 × the 7th number?
- 34.A leapfrog list starts 4, 7 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 35.2 + 6 + 8 + 14 + 22 + 36 + 58 + 94 + 152 + 246 =
- 36.A leapfrog list starts 9, 9 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 9, 4 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 38.Leapfrog list (each number is the sum of the two before it): 9, 3, 12, 15, 27, 42, 69, 111, 180, 291. What is 11 × the 7th number?
- 39.7 + 2 + 9 + 11 + 20 + 31 + 51 + 82 + 133 + 215 =
- 40.A leapfrog list starts 1, 1 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
Answer key
- 627
- 550
- 495
- 1199
- 726
- 396
- 1067
- 517
- 561
- 473
- 660
- 231
- 341
- 1012
- 825
- 902
- 451
- 627
- 759
- 418
- 979
- 539
- 363
- 968
- 957
- 1122
- 1023
- 286
- 583
- 770
- 836
- 737
- 1056
- 836
- 638
- 1287
- 847
- 759
- 561
- 143
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