$1 2 3 9 = 10$

Full solution

1 2 3 9 = 10

Addition Attempt: question_prompt: How can we make the equation $1 ext{ }2 ext{ }3 ext{ }9$ equal $10$ using basic arithmetic operations?
Sum Calculation: Let's try adding the numbers together first: $1 + 2 + 3 + 9$ .
Different Approach: Calculate the sum: $1 + 2 + 3 + 9 = 15$ .
Multiplication and Subtraction Attempt: $15$ is not equal to $10$ , so let's try a different approach. Maybe we can use subtraction, multiplication, or division.
New Expression Calculation: If we multiply $1$ by $2$ , we get $2$ , and then if we add $3$ and subtract $9$ , maybe we can get $10$ ? So, let's try $(1 \times 2) + 3 - 9$ .
Simplify Calculation: Calculate the new expression: $(1 \times 2) + 3 - 9 = 2 + 3 - 9$ .
Final Result Calculation: Simplify the calculation: $2 + 3 - 9 = 5 - 9$ .
Final Result Calculation: Simplify the calculation: $2 + 3 - 9 = 5 - 9$ . Calculate the final result: $5 - 9 = -4$ .