Let's break down the numbers and order them from greatest to least:

1. 0.7 is already in decimal form.
2. 0.5 is also in decimal form.
3. -7 19/38 is a mixed fraction, and we need to convert it to a decimal for comparison:
   • First, convert the fraction 19/38 to its decimal equivalent: 19/38 = 0.5.
   • So, -7 19/38 = -7.5.
4. 7 is an integer and is already in its simplest form.
5. 24/40 is a fraction, and we need to convert it to a decimal:
   • 24 ÷ 40 = 0.6.

Now, let's compare all these values:

• 7 (the greatest number)
• 0.7 (next)
• 0.6 (next)
• 0.5 (next)
• -7.5 (the least number)

Thus, the order from greatest to least is: 7, 0.7, 0.6, 0.5, -7.5.

Do you need further clarification or details?

Here are some related questions to help expand on this topic:

1. How do you convert a mixed fraction into a decimal?
2. What is the process for comparing fractions and decimals?
3. How do you convert a fraction like 24/40 to its simplest form?
4. How do negative numbers compare to positive numbers when ordering them?
5. What is the importance of understanding decimals and fractions in real-life situations?

Tip: Always convert fractions to decimals or vice versa when comparing numbers to make the process easier!