multiplication lives
DESCRIPTION
Multiplication Lives. Cuneiform tablet found in West Asia about 2700 BC The table helps people figure out the area of a region by multiplying width by length. The first column is the width, the second is the length, and the third column is the area. - PowerPoint PPT PresentationTRANSCRIPT
MultiplicationLives
•Cuneiform tablet found in West Asia about 2700 BC
•The table helps people figure out the area of a region by multiplying width by length.
•The first column is the width, the second is the length, and the third column is the area.
•It uses a system for writing down large numbers in base 60 (the way our clocks work today).
Let’s analyze what’s happening.
Simplest type problem:
2 x 3= 6
4 x 5= 20
What about a problem like this?
13 x 4The intersection of 13 lines 4 lines.
10 lines
10 points
4
12+
= 52
Sample Problem: 12 x 234
12 x 234100
10
10
1
1
(1 x 3)100
(1 x 2)1000
(2 x 2)100
(1 x 4)10
(2 x 3)10
(2 x 4)1
2 710 8
2808
a b c x d e f
a
c
d
e
f
10000
100
1000
10
100
1
b
100
10
100
1
1
10
1000
100
10
a b c x d
e
f
1001,00010,000
ad ae+bd af+be+cd bf+ce cf10 1
a b cd e fx
a b cd e fx
fcfbfaeceb
dceadbda+
cfbfafcebe
cdaebdad
1001,00010,000
ad ae+bd af+be+cd bf+ce cf10 1
a b c x d
e
f
a.bc x de.f
a
c
d
e
f
b
10?
10?
10?
10?
10?
10?
a.bc x de.f
a
c
d
e
f
b
101
100
100
10-1
10-2
10-1
Decimal Multiplication
€
2.1× 3.27 = 21×1
10
⎛
⎝ ⎜
⎞
⎠ ⎟× 327 ×
1
100
⎛
⎝ ⎜
⎞
⎠ ⎟
€
= 21× 327( ) ×1
10×
1
100
⎛
⎝ ⎜
⎞
⎠ ⎟
€
= 6867( ) ×1
1000
⎛
⎝ ⎜
⎞
⎠ ⎟
€
=6.867