diff --git a/1ano/fp/aula07/coins.py b/1ano/fp/aula07/coins.py
index c5f4f3c..b2aff83 100755
--- a/1ano/fp/aula07/coins.py
+++ b/1ano/fp/aula07/coins.py
@@ -6,48 +6,72 @@
 # Face values of coins (in cents):
 COINS = [200, 100, 50, 20, 10, 5, 2, 1]
 
+
 def value(bag):
     """Return total amount in a bag."""
-    ...
+    totalValue = 0
+    for coin in bag:
+        totalValue += bag[coin] * coin
+    return totalValue
 
 
 def transfer1coin(bag1, c, bag2):
     """Try to transfer one coin of value c from bag1 to bag2.
     If possible, transfer coin and return True, otherwise return False."""
-    ...
+    if bag1[c] == 0:
+        return False
+
+    bag1[c] -= 1
+    bag2[c] = 1 if c not in bag2 else bag2[c] + 1
+
+    return True
 
 
 def transfer(bag1, amount, bag2):
     """Try to transfer an amount from bag1 to bag2.
     If possible, transfer coins and return True,
     otherwise, return False and leave bags with same values."""
+
+    # Creates a backup of the bags in case the transfer is not possible
+    bagBackup = (bag1.copy(), bag2.copy())
+
+    for coin in COINS:
+        while amount >= coin and transfer1coin(bag1, coin, bag2) and amount > 0:
+            amount -= coin
+
     if amount == 0:
         return True
-    if value(bag1) < amount:
-        return False
-    ...
-            
+
+    for coin in COINS:
+        bag1[coin] = bagBackup[0][coin] if coin in bagBackup[0] else 0
+        bag2[coin] = bagBackup[1][coin] if coin in bagBackup[1] else 0
+    return False
+
 
 def strbag(bag):
     """Return a string representing the contents of a bag.""" 
     # You may want to change this to produce a more user-friendly
     # representation such as "4x200+3x50+1x5+3x1=958".
-    return str(bag)
-    ...
+    string = ""
+    for coin in bag:
+        if bag[coin] != 0:
+            string = f"+{bag[coin]}x{coin}{string}"
+    string = f"{string[1:]}={value(bag)}"
+    return string
 
 
 def main():
     # A bag of coins is represented by a dict of {coin: number} items
-    bag1 = {1: 4, 2: 0, 5:1, 10: 0, 20: 5, 50: 4, 100: 2, 200: 1}
+    bag1 = {1: 4, 2: 0, 5: 1, 10: 0, 20: 5, 50: 4, 100: 2, 200: 1}
     bag2 = {}
 
     # Test the value function.
     assert value({}) == 0
-    assert value({1:7, 5:2, 20:4, 100:1}) == 197
+    assert value({1: 7, 5: 2, 20: 4, 100: 1}) == 197
 
     # Test the strbag function.
-    print( strbag({1:7, 5:2, 20:4, 100:1}) )        # 1x100+4x20+2x5+7x1=197
-    print( strbag({1:7, 5:2, 10:0, 20:4, 100:1}) )  # 1x100+4x20+2x5+7x1=197
+    print(strbag({1: 7, 5: 2, 20: 4, 100: 1}))         # 1x100+4x20+2x5+7x1=197
+    print(strbag({1: 7, 5: 2, 10: 0, 20: 4, 100: 1}))  # 1x100+4x20+2x5+7x1=197
 
     print("bag1:", strbag(bag1))    # bag1: 1x200+2x100+4x50+5x20+1x5+4x1=709
     print("bag2:", strbag(bag2))    # bag2: =0
@@ -74,6 +98,7 @@ def main():
 
     return
 
+
 if __name__ == "__main__":
     main()