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055_G3U11_G4U18_˙—» ¿º 2011.3.22 9:1 PM ˘ ` 100 PDF_In 2540DPI 150LPI T
UNIT
11 The Magic Rods
In the 17th century, an English mathematician named 38
John Napier invented a tool called Napier’s Rods
to make multiplication faster and easier. 1 00
38
2 01
66
3 02
94
4 13
22
5 14
50
6 14
85
7 25
16
8 26
44
9 27
72
Napier’s Rods
Use Napier’s Rods to multiply.
38 ^ 4 152 38 38
1 34 1 34
38
34 22 22
2
Multiply the tens. 152
Multiply the ones.
Add the numbers in
the diagonal.
5 7 24
1 3 8
5
100
UNIT
11 The Magic Rods
In the 17th century, an English mathematician named 38
John Napier invented a tool called Napier’s Rods
to make multiplication faster and easier. 1 00
38
2 01
66
3 02
94
4 13
22
5 14
50
6 14
85
7 25
16
8 26
44
9 27
72
Napier’s Rods
Use Napier’s Rods to multiply.
38 ^ 4 152 38 38
1 34 1 34
38
34 22 22
2
Multiply the tens. 152
Multiply the ones.
Add the numbers in
the diagonal.
5 7 24
1 3 8
5
100
