1. The problem is to understand the place values of digits in three-digit numbers and how to break down numbers into hundreds, tens, and units. 2. Each three-digit number can be expressed as the sum of its hundreds, tens, and units digits multiplied by their place values. 3. The formula for a three-digit number $ABC$ is: $$ABC = A \times 100 + B \times 10 + C$$ where $A$ is the hundreds digit, $B$ is the tens digit, and $C$ is the units digit. 4. For example, for the number 688: - Hundreds digit: 6 - Tens digit: 8 - Units digit: 8 So, $$688 = 6 \times 100 + 8 \times 10 + 8$$ 5. To solve the problems with missing digits (☐), identify the known digits and place values, then use the formula to find the missing digits. 6. For example, if the number is ☐44 and the hundreds digit is 7, then: $$\boxed{7}44 = 7 \times 100 + 4 \times 10 + 4 = 700 + 40 + 4 = 744$$ 7. Similarly, for 6☐1 with tens digit 7: $$6\boxed{7}1 = 6 \times 100 + 7 \times 10 + 1 = 600 + 70 + 1 = 671$$ 8. For the sums like 875 = ☐ + ☐ + ☐, break the number into hundreds, tens, and units: $$875 = 800 + 70 + 5$$ So the digits are 8, 7, and 5 respectively. 9. This method applies to all the given numbers and missing digit problems. 10. Practice by identifying each digit's place value and reconstructing the number accordingly. This approach helps understand the structure of three-digit numbers and solve for missing digits easily.