5. Complete these number sentences. Check each answer by substitution. a) \( 23405+\square=42000 \) b) \( \square+350000=500000 \) c) \( \square-45347=950000 \)

Sure, let's complete each number sentence and verify the solutions by substitution. --- **a) \( 23,405 + \square = 42,000 \)** **Solution:** To find the value of the square: \[ \square = 42,000 - 23,405 = 18,595 \] **Check by Substitution:** \[ 23,405 + 18,595 = 42,000 \] --- **b) \( \square + 350,000 = 500,000 \)** **Solution:** To find the value of the square: \[ \square = 500,000 - 350,000 = 150,000 \] **Check by Substitution:** \[ 150,000 + 350,000 = 500,000 \] --- **c) \( \square - 45,347 = 950,000 \)** **Solution:** To find the value of the square: \[ \square = 950,000 + 45,347 = 995,347 \] **Check by Substitution:** \[ 995,347 - 45,347 = 950,000 \] --- Each solution satisfies the original equation when substituted back, confirming that the answers are correct.