﻿ Using for and range

### Using for and range() for looping

```
# to print out numbers from 0 to 10:
for i in range(11):
print(i)

# to print out numbers from 5 to 12:
for i in range(5,13):
print(i)

# to add up the numbers from 1 to 100:
total = 0
for i in range(1,101):
total += i

# using "break" to add up the numbers from 1 to 100:
total = 0
for i in range(1,100000000):
total += i
if i == 100:
break

# Create a function addToLCM(fred,george) which adds up all the numbers from 1 until the
#    first number that is evenly divisible by both fred and george:
# We know that the number fred*george is evenly divisible by both fred and george, but a
#   smaller number may also be (for instance if fred = 4 and george = 8, then the smallest
#   number evenly divisible by 4 and 8 is 8, not 32).

total = 0
for i in range(1,fred*george+1):
total += i
if i % fred == 0 and i % george == 0:
break

# Create a function that shows that the sum of the numbers from 1 to N equals N*(N+1)/2
def proveIt(N):
total = 0
for i in range(N+1):
total += i
print(total,'should be',N*(N+1)/2)

# we know that sum: 1/2 + 1/4 + 1/8 + 1/16 + ... gets closer and closer to 1.0.
# Create a function howMany(teeny) that will tell us how many terms we need to add so that
#  the sum is closer to 1 than teeny.  Assume that teeny is very small.
def howMany(teeny):
total = 0
for i in range(1,1000000):
total += 1/(2**i)
if abs(1 - total) < teeny:
return i

```