Respuesta :

LukeAmos

Answer:

100

1800

900

1600

Step-by-step explanation:

Easy way to solve :

remove the 0's eg

20*90 -> 2*9 = 18

then add the 0's back on

1800

Answer:

See below ↓↓↓↓

Step-by-step explanation:

  1. 10 x 10 = 100
  2. 20 x 90 = 1800
  3. 30 x 30 = 900
  4. 40 x 40 = 1600