сколько будет 4*5

Here is a clear, step-by-step solution in English, suitable for a 6th-grade level.

Problem: What is 4 × 5?

Step 1 — Interpret the expression

• 4 × 5 means four groups of five, or five groups of four. The product is the same regardless of how you group it due to the commutative property of multiplication.

Step 2 — Repeated addition (a common mental model)

• 4 × 5 can be seen as adding 4 together five times: 4 + 4 + 4 + 4 + 4 = 20

Step 3 — Visual/array model (optional)

• Imagine an array with 4 rows and 5 columns (or 5 rows and 4 columns). Counting all the dots gives 4 × 5 = 20.

Step 4 — Quick check using the table or commutativity

• Since multiplication is commutative, 4 × 5 = 5 × 4.
• From the basic multiplication table, 5 × 4 = 20, which confirms the result.

Answer: 20

If you’d like, I can provide more methods (e.g., doubling, decomposition) or translate this explanation into Russian.