Tập hợp B gồm các số lẻ có 4 chữ số abcd có tính chất a + d = b - c = 5 có thể được viết như sau:

B = {1537, 1546, 1555, 1564, 1573, 1627, 1636, 1645, 1654, 1663, 1717, 1726, 1735, 1744, 1753, 1817, 1826, 1835, 1844, 1853, 1917, 1926, 1935, 1944, 1953, 2017, 2026, 2035, 2044, 2053, 2117, 2126, 2135, 2144, 2153, 2217, 2226, 2235, 2244, 2253, 2317, 2326, 2335, 2344, 2353, 2417, 2426, 2435, 2444, 2453, 2517, 2526, 2535, 2544, 2553, 2617, 2626, 2635, 2644, 2653, 2717, 2726, 2735, 2744, 2753, 2817, 2826, 2835, 2844, 2853, 2917, 2926, 2935, 2944, 2953, 3017, 3026, 3035, 3044, 3053, 3117, 3126, 3135, 3144, 3153, 3217, 3226, 3235, 3244, 3253, 3317, 3326, 3335, 3344, 3353, 3417, 3426, 3435, 3444, 3453, 3517, 3526, 3535, 3544, 3553, 3617, 3626, 3635, 3644, 3653, 3717, 3726, 3735, 3744, 3753, 3817, 3826, 3835, 3844, 3853, 3917, 3926, 3935, 3944, 3953, 4017, 4026, 4035, 4044, 4053, 4117, 4126, 4135, 4144, 4153, 4217, 4226, 4235, 4244, 4253, 4317, 4326, 4335, 4344, 4353, 4417, 4426, 4435, 4444, 4453, 4517, 4526, 4535, 4544, 4553, 4617, 4626, 4635, 4644, 4653, 4717, 4726, 4735, 4744, 4753, 4817, 4826, 4835, 4844, 4853, 4917, 4926, 4935, 4944, 4953, 5017, 5026, 5035, 5044, 5053, 5117, 5126, 5135, 5144, 5153, 5217, 5226, 5235, 5244, 5253, 5317, 5326, 5335, 5344, 5353, 5417, 5426, 5435, 5444, 5453, 5517, 5526, 5535, 5544, 5553, 5617, 5626, 5635, 5644, 5653, 5717, 5726, 5735, 5744, 5753, 5817, 5826, 5835, 5844, 5853, 5917, 5926, 5935, 5944, 5953, 6017, 6026, 6035, 6044, 6053, 6117, 6126, 6135, 6144, 6153, 6217, 6226, 6235, 6244, 6253, 6317, 6326, 6335, 6344, 6353, 6417, 6426, 6435, 6444, 6453, 6517, 6526, 6535, 6544, 6553, 6617, 6626, 6635, 6644, 6653, 6717, 6726, 6735, 6744, 6753, 6817, 6826, 6835, 6844, 6853, 6917, 6926, 6935, 6944, 6953, 7017, 7026, 7035, 7044, 7053, 7117, 7126, 7135, 7144, 7153, 7217, 7226, 7235, 7244, 7253, 7317, 7326, 7335, 7344, 7353, 7417, 7426, 7435, 7444, 7453, 7517, 7526, 7535, 7544, 7553, 7617, 7626, 7635, 7644, 7653, 7717, 7726, 7735, 7744, 7753, 7817, 7826, 7835, 7844, 7853, 7917, 7926, 7935, 7944, 7953, 8017, 8026, 8035, 8044, 8053, 8117, 8126, 8135, 8144, 8153, 8217, 8226, 8235, 8244, 8253, 8317, 8326, 8335, 8344, 8353, 8417, 8426, 8435, 8444, 8453, 8517, 8526, 8535, 8544, 8553, 8617, 8626, 8635, 8644, 8653, 8717, 8726, 8735, 8744, 8753, 8817, 8826, 8835, 8844, 8853, 8917, 8926, 8935, 8944, 8953, 9017, 9026, 9035, 9044, 9053, 9117, 9126, 9135, 9144, 9153, 9217, 9226, 9235, 9244, 9253, 9317, 9326, 9335, 9344, 9353, 9417, 9426, 9435, 9444, 9453, 9517, 9526, 9535, 9544, 9553, 9617, 9626, 9635, 9644, 9653, 9717, 9726, 9735, 9744, 9753, 9817, 9826, 9835, 9844, 9853, 9917, 9926, 9935, 9944, 9953}