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Exercise 2.9, , 1. Find the estimated answers :, (a) 753 + 525, (b) 11526 + 8748, (c) 980 — 489, (d) 5897 — 2987, — (e) 440 x 28
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i, , 5, , f, s, , (g) 563 + 34, (h) 7541 + 43, Sol., » (a) 753 rounded off = 800, : 525 rounded off = + 500, Estimated sum = “7300(b) 11526 rounded off = 600,, 8748 rounded off = + 9000, Estimated sum = "21000, (c) 980 rounded off = 1600,, 489 rounded off = —500, Estimated difference = __500, () 5897 rounded off = 6000, 2987 rounded off = 3000, Estimated difference = _ 3000, (e) 440 rounded off = — 490, 28 rounded off = 30, - 400, x 30, Estimated product 12000, () 6198 rounded off = 6000, 13 rounded off = a, Estimated product = 6000 x 10 = 60000, (g) 563 rounded off = 600, ' 34 rounded off = #, ' Estimated value = 600 + 30 = a, E(t) 7541 rounded off = 8000, 43 rounded off = aoe, Ba Jvalue = 8000+ 40= _200, , , , - ( 6198x13
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Exercise 2.10, , , , Solve the following :, , Oo ONAN PWN =, , ope eS, , -42+74+8, -8+6x2, -7x8+4-6, , .63 +9x 44+ 28-15, .25x3+42+6-4, , . 18 + 6x 21+ 17-18, -8+8+8x8-8, , . 72 + 48 x 36 + 18-9, , 4442x9-35 +5, , . 18 + 126 + 14x 3-25, , 42+7+8=64+8=14, 8+6x2=8+12=20, 7x8+4-6, , = 7x2-6, , = 14-6=8, , 63 +9x4+ 28-15, = 7x4+28-15, , = 28+28-15, , = 56-15, , = 41, 25x3+42+6-4, 21: 2x347-4, , = 75+7-4, , = §82-4, , = 78 j, , 18 + 6x 214 17-18, = 3x21+4+17-18
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= 63+17-18 9.44+2x9-3525, = 80-18 = 444+2x9-7 |, se = 444+18-7, 8 =84+8x8-8 = 62-7, , = 1+8x8-8 - 55, , = 1+64-8, , Ses 10. 18 + 126 + 14x 3-25, , - 37 = 18+9x3-25, , 72+ 48 x 36 + 18-9 = 18+27-25, , = 72+48x2-9 = 45-25, , = 72+96-9 = 20, , = 168-9, , = 159.