Multiplication pyramid

5 x 15 =75

5 x 10 = 50

5 x 5 = 25

50 + 25 = 75

15 x 12 = 180

12 x 10 = 120

12 x 5 = 60

120 + 60 = 180

12 x 4 = 48

10 x 4 = 40

2 x 4 = 8

40 + 8 = 48

75 x 180 =

70 x 100 = 7000

70 x 80 = 5600

5 x 100 = 500

5 x 80 = 400

7000 + 5600 = 12600

500 + 400 = 900

12600 + 900 = 13500

180 x 48 =

40 x 100 = 4000

40 x 80 = 3200

8 x 100 = 800

8 x 80 = 640

4000 + 3200 = 7200

800 + 640 = 1440

7200 + 1440 = 8640

13500 x 8640 =

8640 x 10000 = 86400000

8640 x 3000 =25920000

8640 x 500 = 4320000

86400000 + 25920000 + 4320000 = 116640000