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Academic Skills Advice Four Rules Refresher Sheet 2 Multiplication using Box Method: Separate your numbers out (e.g. write 64 as 60+4) then draw a grid with each part number as a row or column heading. Do each multiplication then add all the boxes together. Remember the easy way for multiplying numbers with zero’s (e.g. 40x600 = 4x6 = 24 then add the 3 0’s = 24000). Example: 64 x 23 60 4 20 1200 80 1st fill in each square. The gray square is 20x60 so the answer is 1200. 3 180 12 Now just add all the boxes together: 1200+80+180+12 = 1472 Multiplication using Grid method: Draw a grid for your numbers and fill in the boxes with the appropriate answers. Add the diagonals. Example: 64 x 23 6 2 1 1 3 1 2 8 2 1 4 8 1 8 1 8 1st fill in each square. The gray square is 2x6 so the answer 12 has been filled in. 2 0 1 1 4 0 2 Then add each diagonal from the right, the first one is just 2. The next diagonal (shown in gray) is 8+1+8=17 so ‘7 down’, ‘carry 1’. The next is 0+2+1+1(carried)= 4, the last one is just 1) 7 2 © H Jackson 2008 / Academic Skills 1 Practice Questions: Do the following multiplications: 2 x x 4 6 7 5 x 6 5 3 x 5 8 © H Jackson 2008 / Academic Skills 3 4 x 4 9 5 x 3 2 6 6 x 4 4 7 x 4 3 5 6 5 7 x 7 7 x 2 3 4 8 5 4 8 5 7 2