20•20+50:10

To solve the expression \(20 \cdot 20 + 50 \div 10\), follow the order of operations (PEMDAS/BODMAS):

1. Multiplication and Division (from left to right):

   • \(20 \cdot 20 = 400\)
   • \(50 \div 10 = 5\)

2. Addition:

   • \(400 + 5 = 405\)

So, \(20 \cdot 20 + 50 \div 10 = 405\).