year3
TRANSCRIPT
9 X 4 = 369 X 4 = 36
MultiplicandMultiplicand MultiplierMultiplier ProductProduct
MULTIPLICATION
MULTIPLICATIONMULTIPLICATION(2-digit number x 1-digit number)
TYPE 1TYPE 1
Both of the products are less than 10
( without regrouping )
Example: 13 × 2 Example: 13 × 2 ==
How do we calculateHow do we calculate on the abacuson the abacus??
13 X 2 =13 X 2 =• Step 1Step 1 2 X 1 = 02
(start from the first rod on the left)
• Step 2Step 2 2 X 3 = 06 (start from the second rod on the left)
• The product is 26The product is 26
• 11 X 2 =11 X 2 =
• 13 X 2 =13 X 2 =
• 22 X 2 =22 X 2 =
• 24 X 2 =24 X 2 =
• 33 X 2 =33 X 2 =
• 41 X 2 =41 X 2 =
Calculate with abacus
• 31 X 3 =31 X 3 =
• 22 X 3 =22 X 3 =
• 12 X 4 =12 X 4 =
• 22 X 4 =22 X 4 =
• 11 X 6 =11 X 6 =
• 11 X 9 =11 X 9 =
Calculate with abacus
Mental Calculation
Ready, close your eyes.
14 14 XX 2 = 2 =
2X1=02
2X4=08
Equals 28Equals 28
TYPE 2TYPE 2
One of the products is more than 10 (tens)
One of the products is less than 10 (ones)
( without regrouping )
ExampleExample: 31 X 4 =: 31 X 4 =
How do we calculateHow do we calculate on the abacuson the abacus??
31 X 4 =
• Step 1Step 1 4 X 3 = 12
(start from the first rod on the left)
• Step 2Step 2 4 X 1 = 04 (start from the second rod on the left)
• The product is 124
• 51 X 2 =51 X 2 =
• 72 X 2 =72 X 2 =
• 93 X 2 =93 X 2 =
• 81 X 3 =81 X 3 =
• 42 X 3 =42 X 3 =
• 63 X 3 =63 X 3 =
Calculate with abacus
• 31 X 4 =31 X 4 =
• 21 X 5 =21 X 5 =
• 91 X 6 =91 X 6 =
• 61 X 9 =61 X 9 =
• 51 X 7 =51 X 7 =
• 81 X 8 =81 X 8 =
Calculate with abacus
Mental Mental CalculationCalculation
Ready, close your eyes.Ready, close your eyes.
63 X 2 =63 X 2 =
2X6=12
2X3=06
Equals 126
TYPE 3
One of the products is the multiple of 10 (tens)
One of the products is more than 10 (ones)
( without regrouping )
Example: 43 X 5 =
How do we calculateHow do we calculate on the abacuson the abacus??
43 X 5 =
• Step 1Step 1 5 X 4 = 20
(start from the first rod on the left)
• Step 2Step 2 5 X 3 = 15 (start from the second rod on the left)
• The product is 215
• 158 X 2 =158 X 2 =• 157 X 4 =157 X 4 =• 123 X 5 =123 X 5 =• 148 X 5 =148 X 5 =• 153 X 6 =153 X 6 =• 159 X 8 =159 X 8 =
Calculate with abacus
Calculate with abacus
• 184 X 5 =184 X 5 =• 124 X 3 =124 X 3 =• 956 X 1 =956 X 1 =• 100 X 5 =100 X 5 =• 315 X 2 =315 X 2 =• 182 X 3 =182 X 3 =
Mental Calculation
Ready, close your eyes.
67 X 5 =
5X6=30
5X7=35
Equals 335
TYPE 4
One of the products is less than 10 (tens)
One of the products is more than 10 (ones)
( without regrouping )
Example: 15 X 4 =
How do we calculateHow do we calculate on the abacuson the abacus??
15 X 4 =• Step 1Step 1 4 X 1 = 04
(start from the first rod on the left)
• Step 2Step 2 4 X 5 = 20 (start from the second rod on the left)
• The product is 60The product is 60
• 118 X 2 =118 X 2 =
• 215 X 3 =215 X 3 =
• 127 X 4 =127 X 4 =
• 142 X 5 =142 X 5 =
• 133 X 6 =133 X 6 =
• 214 X 2 =214 X 2 =
Calculate with abacus
Mental Calculation
Ready, close your eyes.
26 X 3 =
3X2=06
3X6=18
Equals 78
TYPE 5
One of the products is less than 10 (tens)
One of the products is more than 10 (ones)
( with regrouping at tens )
Example: 16 X 7 =
How do we calculateHow do we calculate on the abacuson the abacus??
16 X 7 =• Step 1Step 1 7 X 1 = 07
(start from the first rod on the left)
• Step 2Step 2 7 X 6 = 42 (start from the second rod on the left)
• The product is 112The product is 112
• 139 X 3 =139 X 3 =• 16 X 9 =16 X 9 =• 113 X 8 =113 X 8 =• 129 X 4 =129 X 4 =• 414 X 2 =414 X 2 =• 896 X 1 =896 X 1 =
Calculate with abacus
Mental Calculation
Ready, close your eyes.
26 X 4 =
4X2=084X6=24
Equals 104
TYPE 6
Both of the products are more than 10
( without regrouping )
Example: 35 X 4 =
How do we calculateHow do we calculate on the abacuson the abacus??
35 X 4 =
• Step 1Step 1 4 X 3 = 12
(start from the first rod on the left)
• Step 2Step 2 4 X 5 = 20 (start from the second rod on the left)
• The product is 140
• 197 X 5 =197 X 5 =• 263 X 4 =263 X 4 =• 199 X 7 =199 X 7 =• 272 X 6 =272 X 6 =• 385 X 2 =385 X 2 =• 246 X 3 =246 X 3 =
Calculate with abacus
Mental Calculation
Ready, close your eyes.
64 X 3 =64 X 3 =
3X6=183X4=12
Equals 192
TYPE 7
Both of the products are more than 10
( with regrouping at tens )
Example: 29 X 7 =
How do we calculateHow do we calculate on the abacuson the abacus??
29 X 7 =• Step 1Step 1 7 X 2 = 14
(start from the first rod on the left)
• Step 2Step 2 7 X 9 = 63 (start from the second rod on the left)
• The product is 203
• 115 X 9 =115 X 9 =• 234 X 3 =234 X 3 =• 127 X 6 =127 X 6 =• 376 X 2 =376 X 2 =• 443 X 2 =443 X 2 =• 184 X 6 =184 X 6 =
Calculate with abacus
Mental Calculation
Ready, close your eyes.
84 X 4 =
4X8=32
4X4=16
Equals 336
THE THE ENDEND
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