A has 50 non-zero entries:
3: (3, -7433.3) (9, -7044.9) 
4: (5, -6018.9) (8, 2116.6) (12, -815.1) (14, -8592.6) 
5: (3, -9731.7) (13, -3487.3) (20, 4706.0) 
7: (4, 3252.7) (10, 5485.6) (16, -3544.5) (20, 7494.4) 
8: (1, 2195.8) 
9: (4, -1331.4) (5, 6744.1) (16, 4347.5) (20, 3768.4) 
10: (3, 8128.7) (4, -9090.5) (9, 8080.1) (15, -8204.6) 
11: (2, -5704.5) (10, -8284.5) (16, -3048.2) 
12: (1, -5040.3) (8, -2840.7) (10, 4934.7) (11, 3548.5) 
13: (15, 8622.2) (17, 9768.6) 
14: (9, 9142.2) 
15: (2, -7389.8) (6, 8410.6) 
16: (16, -9176.0) (17, -3214.9) 
17: (5, -9011.6) (20, 3194.6) 
18: (6, -5813.5) (11, -334.1) (12, 8941.3) 
19: (1, 2848.7) (7, -1429.9) (8, 4750.6) (15, 325.2) (16, 36.2) 
20: (7, -3490.5) (16, -6639.6) (17, -1453.4) (18, 2112.4) 

B has 40 non-zero entries:
1: (6, -7607.6) 
2: (2, 9792.3) 
3: (14, 3717.5) 
4: (8, 7726.8) (9, -5056.4) (16, 4544.1) (20, -4788.1) 
5: (4, 3948.1) (6, 650.6) (11, -6087.6) 
6: (6, -3442.1) (8, 6019.1) (17, -6543.7) 
8: (2, 8989.5) (6, -605.6) (17, 7789.1) 
9: (7, -4702.6) (8, 2218.0) (9, 3894.5) 
10: (2, -1821.5) (7, 2671.7) (12, -7499.9) (17, -3793.7) 
11: (13, 2285.5) 
13: (3, -9078.3) (8, 9314.0) (9, -3934.8) 
14: (2, 8936.5) (9, 2346.3) 
16: (7, 7374.4) 
17: (20, -6863.8) 
18: (2, -7953.6) (6, -390.0) (12, -314.5) (13, 3324.5) 
19: (5, -1692.8) (12, -7007.8) (15, -8201.1) 
20: (2, 2141.8) (15, 9038.8) 

(1.5)*A =
3: (3, -11150.0) (9, -10567.3) 
4: (5, -9028.3) (8, 3174.9) (12, -1222.7) (14, -12888.9) 
5: (3, -14597.6) (13, -5231.0) (20, 7059.0) 
7: (4, 4879.0) (10, 8228.4) (16, -5316.8) (20, 11241.6) 
8: (1, 3293.7) 
9: (4, -1997.1) (5, 10116.2) (16, 6521.2) (20, 5652.6) 
10: (3, 12193.0) (4, -13635.8) (9, 12120.2) (15, -12306.9) 
11: (2, -8556.8) (10, -12426.8) (16, -4572.3) 
12: (1, -7560.5) (8, -4261.0) (10, 7402.0) (11, 5322.8) 
13: (15, 12933.3) (17, 14652.9) 
14: (9, 13713.3) 
15: (2, -11084.7) (6, 12615.9) 
16: (16, -13764.0) (17, -4822.4) 
17: (5, -13517.4) (20, 4791.9) 
18: (6, -8720.2) (11, -501.2) (12, 13411.9) 
19: (1, 4273.0) (7, -2144.9) (8, 7125.9) (15, 487.8) (16, 54.3) 
20: (7, -5235.8) (16, -9959.4) (17, -2180.1) (18, 3168.6) 

A+B =
1: (6, -7607.6) 
2: (2, 9792.3) 
3: (3, -7433.3) (9, -7044.9) (14, 3717.5) 
4: (5, -6018.9) (8, 9843.4) (9, -5056.4) (12, -815.1) (14, -8592.6) (16, 4544.1) (20, -4788.1) 
5: (3, -9731.7) (4, 3948.1) (6, 650.6) (11, -6087.6) (13, -3487.3) (20, 4706.0) 
6: (6, -3442.1) (8, 6019.1) (17, -6543.7) 
7: (4, 3252.7) (10, 5485.6) (16, -3544.5) (20, 7494.4) 
8: (1, 2195.8) (2, 8989.5) (6, -605.6) (17, 7789.1) 
9: (4, -1331.4) (5, 6744.1) (7, -4702.6) (8, 2218.0) (9, 3894.5) (16, 4347.5) (20, 3768.4) 
10: (2, -1821.5) (3, 8128.7) (4, -9090.5) (7, 2671.7) (9, 8080.1) (12, -7499.9) (15, -8204.6) (17, -3793.7) 
11: (2, -5704.5) (10, -8284.5) (13, 2285.5) (16, -3048.2) 
12: (1, -5040.3) (8, -2840.7) (10, 4934.7) (11, 3548.5) 
13: (3, -9078.3) (8, 9314.0) (9, -3934.8) (15, 8622.2) (17, 9768.6) 
14: (2, 8936.5) (9, 11488.5) 
15: (2, -7389.8) (6, 8410.6) 
16: (7, 7374.4) (16, -9176.0) (17, -3214.9) 
17: (5, -9011.6) (20, -3669.2) 
18: (2, -7953.6) (6, -6203.5) (11, -334.1) (12, 8626.8) (13, 3324.5) 
19: (1, 2848.7) (5, -1692.8) (7, -1429.9) (8, 4750.6) (12, -7007.8) (15, -7875.9) (16, 36.2) 
20: (2, 2141.8) (7, -3490.5) (15, 9038.8) (16, -6639.6) (17, -1453.4) (18, 2112.4) 

A+A =
3: (3, -14866.6) (9, -14089.8) 
4: (5, -12037.8) (8, 4233.2) (12, -1630.2) (14, -17185.2) 
5: (3, -19463.4) (13, -6974.6) (20, 9412.0) 
7: (4, 6505.4) (10, 10971.2) (16, -7089.0) (20, 14988.8) 
8: (1, 4391.6) 
9: (4, -2662.8) (5, 13488.2) (16, 8695.0) (20, 7536.8) 
10: (3, 16257.4) (4, -18181.0) (9, 16160.2) (15, -16409.2) 
11: (2, -11409.0) (10, -16569.0) (16, -6096.4) 
12: (1, -10080.6) (8, -5681.4) (10, 9869.4) (11, 7097.0) 
13: (15, 17244.4) (17, 19537.2) 
14: (9, 18284.4) 
15: (2, -14779.6) (6, 16821.2) 
16: (16, -18352.0) (17, -6429.8) 
17: (5, -18023.2) (20, 6389.2) 
18: (6, -11627.0) (11, -668.2) (12, 17882.6) 
19: (1, 5697.4) (7, -2859.8) (8, 9501.2) (15, 650.4) (16, 72.4) 
20: (7, -6981.0) (16, -13279.2) (17, -2906.8) (18, 4224.8) 

B-A =
1: (6, -7607.6) 
2: (2, 9792.3) 
3: (3, 7433.3) (9, 7044.9) (14, 3717.5) 
4: (5, 6018.9) (8, 5610.2) (9, -5056.4) (12, 815.1) (14, 8592.6) (16, 4544.1) (20, -4788.1) 
5: (3, 9731.7) (4, 3948.1) (6, 650.6) (11, -6087.6) (13, 3487.3) (20, -4706.0) 
6: (6, -3442.1) (8, 6019.1) (17, -6543.7) 
7: (4, -3252.7) (10, -5485.6) (16, 3544.5) (20, -7494.4) 
8: (1, -2195.8) (2, 8989.5) (6, -605.6) (17, 7789.1) 
9: (4, 1331.4) (5, -6744.1) (7, -4702.6) (8, 2218.0) (9, 3894.5) (16, -4347.5) (20, -3768.4) 
10: (2, -1821.5) (3, -8128.7) (4, 9090.5) (7, 2671.7) (9, -8080.1) (12, -7499.9) (15, 8204.6) (17, -3793.7) 
11: (2, 5704.5) (10, 8284.5) (13, 2285.5) (16, 3048.2) 
12: (1, 5040.3) (8, 2840.7) (10, -4934.7) (11, -3548.5) 
13: (3, -9078.3) (8, 9314.0) (9, -3934.8) (15, -8622.2) (17, -9768.6) 
14: (2, 8936.5) (9, -6795.9) 
15: (2, 7389.8) (6, -8410.6) 
16: (7, 7374.4) (16, 9176.0) (17, 3214.9) 
17: (5, 9011.6) (20, -10058.4) 
18: (2, -7953.6) (6, 5423.5) (11, 334.1) (12, -9255.8) (13, 3324.5) 
19: (1, -2848.7) (5, -1692.8) (7, 1429.9) (8, -4750.6) (12, -7007.8) (15, -8526.3) (16, -36.2) 
20: (2, 2141.8) (7, 3490.5) (15, 9038.8) (16, 6639.6) (17, 1453.4) (18, -2112.4) 

A-A =

Transpose(A) =
1: (8, 2195.8) (12, -5040.3) (19, 2848.7) 
2: (11, -5704.5) (15, -7389.8) 
3: (3, -7433.3) (5, -9731.7) (10, 8128.7) 
4: (7, 3252.7) (9, -1331.4) (10, -9090.5) 
5: (4, -6018.9) (9, 6744.1) (17, -9011.6) 
6: (15, 8410.6) (18, -5813.5) 
7: (19, -1429.9) (20, -3490.5) 
8: (4, 2116.6) (12, -2840.7) (19, 4750.6) 
9: (3, -7044.9) (10, 8080.1) (14, 9142.2) 
10: (7, 5485.6) (11, -8284.5) (12, 4934.7) 
11: (12, 3548.5) (18, -334.1) 
12: (4, -815.1) (18, 8941.3) 
13: (5, -3487.3) 
14: (4, -8592.6) 
15: (10, -8204.6) (13, 8622.2) (19, 325.2) 
16: (7, -3544.5) (9, 4347.5) (11, -3048.2) (16, -9176.0) (19, 36.2) (20, -6639.6) 
17: (13, 9768.6) (16, -3214.9) (20, -1453.4) 
18: (20, 2112.4) 
20: (5, 4706.0) (7, 7494.4) (9, 3768.4) (17, 3194.6) 

A*B =
3: (7, 33129346.7) (8, -15625588.2) (9, -27436363.0) (14, -27633292.8) 
4: (2, -57760594.2) (4, -23763219.1) (6, -5197709.3) (9, -20160817.4) (11, 36640655.6) (17, 16486409.1) 
5: (2, 10079310.8) (3, 31658755.6) (8, -32480712.2) (9, 13721828.0) (14, -36177594.8) (15, 42536592.8) 
7: (2, 6059485.5) (7, -11482683.3) (8, 25132962.4) (9, -16446952.3) (12, -41141451.4) (15, 67740382.7) (16, 14780594.1) (17, -20810720.7) (20, -15574252.9) 
8: (6, -16704768.1) 
9: (2, 8071159.1) (4, 26626381.2) (6, 4387711.5) (7, 32060204.0) (8, -10287461.5) (9, 6732091.0) (11, -41055383.2) (15, 34061813.9) (16, -6050014.7) (20, 6374876.3) 
10: (7, -37997478.3) (8, -52318813.6) (9, 77433153.7) (14, 30218442.2) (16, -41308141.1) (20, 43526223.1) 
11: (2, -40769958.6) (7, -44612344.7) (12, 62132921.5) (17, 31428907.6) 
12: (2, -34525028.7) (6, 40064914.2) (7, 13184038.0) (12, -37009756.5) (13, 8110096.8) (17, -40847267.8) 
13: (20, -67049716.7) 
14: (7, -42992109.7) (8, 20277399.6) (9, 35604297.9) 
15: (2, -72363138.5) (6, -28950126.3) (8, 50624242.5) (17, -55036443.2) 
16: (7, -67667494.4) (20, 22066430.6) 
17: (2, 6842194.3) (4, -35578698.0) (6, -5862947.0) (11, 54859016.2) (15, 28875350.5) 
18: (6, 20010648.3) (8, -34992037.9) (13, -763585.6) (17, 38041799.9) 
19: (2, 42705518.7) (6, -24548733.5) (7, 266953.3) (17, 37002898.5) 
20: (2, -16801184.6) (6, -823836.0) (7, -48963066.2) (12, -664349.8) (13, 7022673.8) (20, 9975846.9) 

B*B =
1: (6, 26186120.0) (8, -45790905.2) (17, 49781852.1) 
2: (2, 95889139.3) 
3: (2, 33221438.8) (9, 8722370.2) 
4: (2, 59204916.0) (6, -4679350.1) (7, 57288237.7) (8, -11215095.2) (9, -19692149.8) (15, -43278678.3) (17, 60184817.9) 
5: (6, -2239430.3) (8, 34422205.5) (9, -19963172.8) (13, -13913209.8) (16, 17940561.2) (17, -4257331.2) (20, -18903897.6) 
6: (2, 54108699.5) (6, 8202885.4) (8, -20718344.1) (17, 69407441.6) (20, 44914648.1) 
8: (2, 88027880.8) (6, 2084535.8) (8, -3645167.0) (17, 3962864.7) (20, -53462824.6) 
9: (2, 19938711.0) (6, -1343220.8) (7, -18314275.7) (8, 8638001.0) (9, 15167130.2) (17, 17276223.8) 
10: (2, -17836674.4) (20, 26039198.1) 
11: (3, -20748454.6) (8, 21287147.0) (9, -8992985.4) 
13: (2, 83728203.0) (6, -5640558.4) (7, 18503790.5) (8, -8727386.4) (9, -15324078.6) (14, -33748580.2) (17, 72547677.4) 
14: (2, 87508888.9) (7, -11033710.4) (8, 5204093.4) (9, 9137665.4) 
17: (2, -14700886.8) (15, -62040515.4) 
18: (2, -77884037.3) (3, -30180808.3) (6, 1342419.0) (8, 28616944.0) (9, -13081242.6) (17, 2552043.0) 
19: (4, -6683343.7) (6, -1101335.7) (11, 10305089.3) 
20: (2, 20973148.1)