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| Mathematics Magazine for Grades 1-12 |
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| 8/2004 |
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Grade 2
Theory:Ordinal Numbers. Ordinal numbers tell the
position or order of objects. If ten students ran a race, the
student that ran the fastest would be in first place, the next student
would be in second place, and then there would be third, fourth, fifth,
sixth, seventh, eighth, ninth and tenth places. The first ten ordinal numbers
are: First; Second; Third; Fourth; Fifth;
Sixth; Seventh; Eighth; Ninth; Tenth The next ten ordinal numbers are: Eleventh; Twelfth; Thirteenth; Fourteenth; Fifteenth; Sixteenth; Seventeenth; Eighteenth; Nineteenth; Twentieth Solutions from the Previous Issue:Replace the * with numbers 1. *7 + 2 * + *5 = 81 Solution: 27
+ 2 9 + 25 = 81 (7 + 5 + 9 = 21) The sum of units should end in 1 2 + 2 = 4; 8 – 4 = 4 The sum of tenth is 8 The sum of two tenth positions is 4 We have few combinations of 3 numbers that have the sum 4:
27 + 2 9 + 25 = 81 17 + 2 9 + 35 = 81 37 + 2 9 + 15 = 81 07 + 2 9 + 45 = 81 47 + 2 9 + 05 = 81 Proposed Exercises:Recover
the following operations by replacing the
*
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