1. **State the problem:** Jim had his hair cut for 35 and wants to tip the barber 20% of the total cost. 2. **Formula for tip calculation:** Tip amount = Total cost \times Tip percentage 3. **Calculate the tip:** $$\text{Tip} = 35 \times 0.20$$ 4. **Perform the multiplication:** $$\text{Tip} = 7$$ 5. **Interpretation:** Jim should give the barber 7 as a tip, which is 20% of 35. **Final answer:** Jim should tip 7.