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INTEGERS, 7. In a magic square each row, column and diagonal have the same sum. Check which, of the following is a magic square., 5., 4., -5, -2, -4, 7- E-, 3*, -3, 9-, L-|ャ, (1), Verify a-(-b)=a+bfor the following values ofa and b., (1), (i) a = 21, b = 18., (ii) a = 118, b = 125, aces, (iii) a = 75, b = 84, (iv) a= 28, b = 11, 9. Use the sign of >,<or = in the box to make the statements true., (a) (-8) + (- 4), (b) (- 3) +7-(19), the, (c) 23 - 41 + 11, 23-41 11, (d) 39 + (-24)- (15), 36+ (-52)- (- 36), ven, (e) - 231 + 79 + 51, -399 + 159 + 81, 10., 10. A water tank has steps inside it. A monkey is sitting on the topmost step (i.e., the first, step). The water level is at the ninth step., pad, (i) He jumps 3 steps down and then jumps back 2 steps up., In how many jumps will he reach the water level?, (ii) After drinking water, he wants to go back. For this, he, jumps 4 steps up and then jumps back 2 steps down, in every move. In how many jumps will he reach back, the top step?, this, MO, (i11) If the number of steps moved down is represented by, negative integers and the number of steps moved up by, positive integers, represent his moves in part (i) and (ii), by completing the following; (a)- 3+2-... = - 8, (b)4-2+... 8. In (a) the sum (-8) represents going, down by eight steps. So, what will the sum 8 in (b), represent?, 542, June, val., nce, no, 1.3 PROPERTIES OF ADDITION AND SUBTRACTION OF INTEGERS, vill, 1.3.1 Closure under Addition, We have learnt that sum of two whole numbers is again a whole number. For example,, again a whole number. We know that, this property is known as the