4. Look at the window frame highlighted in red colour in the table. a) Find the sum of the two numbers in each row. b) Find the sum of the two numbers in each column. What do you notice? c) Now, find the sum of the numbers in each of the two diagonals marked by arrows. What do you notice? d) Now, put the red window frame in other places and find the sums as above. What do you notice? 5. Identify some patterns and relationships among the numbers in the blue window frame. **Reverse and Add** a) Take a 2-digit number say, 2727. Reverse its digits (7272). Add them (9999). Repeat for different 2-digit numbers. b) What sums can we get when we add a 2-digit number with its reverse? c) List down all numbers which when added to their reverse give i) 5555 ii) 8888 d) Can we get a 3-digit sum? What is the smallest 3-digit sum that we can get? **Fill in the blanks with appropriate numbers.** a) A sequence of trees with numbers inside: Tree 1: 25402540 Tree 2: 25902590 Tree 3: [blank] Tree 4: [blank] Tree 5: [blank] Tree 6: [blank] b) A sequence of capsules/bread shapes with numbers inside: Shape 1: 354354 Shape 2: 13541354 Shape 3: [blank] Shape 4: [blank] Shape 5: [blank] Shape 6: [blank] Shape 7: [blank] c) A number line with equal intervals, a kangaroo positioned on the 4th tick mark, and tick marks having labels or boxes: - Tick 1: 76457645 - Tick 2: 76707670 - Tick 3: [blank box] - Tick 4: [blank box] - Tick 5: 77457745 - Tick 6: [blank box] - Tick 7: [blank box] - Tick 8: [blank box]

Answer: 4 & 5: Underdetermined without page 150 table. Reverse & Add: b) Multiples of 11 (from 11 to 198); c) i) 14, 23, 32, 41, 50; ii) 17, 26, 35, 44, 53, 62, 71, 80; d) Yes, smallest 3-digit sum is 110. Fill in the blanks: a) 2640, 2690, 2740, 2790; b) 2354, 3354, 4354, 5354, 6354; c) 7695, 7720, 7770, 7795, 7820.

Step-by-step solution

Step 1: Analyze Questions 4 and 5

Questions 4 and 5 refer to specific red and blue window frames placed over a number grid located on the preceding page (page 150). Because the table containing those numbers is not visible in this image, Questions 4 and 5 are mathematically underdetermined without that reference grid.

Step 2: Reverse and Add: General Structure and Parts (a) and (b)

For any 22 -digit number with tens digit aa and units digit bb, the number is 10a+b10a + b and its reverse is 10b+a10b + a. Their sum is (10a+b)+(10b+a)=11(a+b)(10a + b) + (10b + a) = 11(a + b). Therefore, any sum obtained by adding a 22 -digit number to its reverse is always a multiple of 1111, ranging from 11×(1+0)=1111 \times (1 + 0) = 11 up to 11×(9+9)=19811 \times (9 + 9) = 198.

Step 3: Reverse and Add: Parts (c) and (d)

For part (c)(i), 11(a+b)=55    a+b=511(a + b) = 55 \implies a + b = 5. With digits a{1,,9}a \in \{1, \dots, 9\} and b{0,,9}b \in \{0, \dots, 9\}, the possible 22 -digit numbers are 14,23,32,41,5014, 23, 32, 41, 50. For (c)(ii), 11(a+b)=88    a+b=811(a + b) = 88 \implies a + b = 8, giving 17,26,35,44,53,62,71,8017, 26, 35, 44, 53, 62, 71, 80. For part (d), yes, we can get a 33 -digit sum when a+b10a + b \ge 10. The smallest sum occurs when a+b=10a + b = 10, which gives 11×10=11011 \times 10 = 110 (for instance, 19+91=11019 + 91 = 110 or 28+82=11028 + 82 = 110).

Step 4: Fill in the Blanks: Pattern (a)

The difference between the first two terms is 25902540=502590 - 2540 = 50. Continuing to add 5050 to each successive term yields: Tree 3: 2590+50=26402590 + 50 = 2640, Tree 4: 2640+50=26902640 + 50 = 2690, Tree 5: 2690+50=27402690 + 50 = 2740, and Tree 6: 2740+50=27902740 + 50 = 2790.

Step 5: Fill in the Blanks: Pattern (b)

The difference between the first two terms is 1354354=10001354 - 354 = 1000. Adding 10001000 to each successive term gives: Shape 3: 23542354, Shape 4: 33543354, Shape 5: 43544354, Shape 6: 53545354, and Shape 7: 63546354.

Step 6: Fill in the Blanks: Number Line (c)

The step size between the first two consecutive tick marks is 76707645=257670 - 7645 = 25. We verify this with Tick 5: 7645+4×25=77457645 + 4 \times 25 = 7745, which matches the given value. Thus, the missing values are: Tick 3: 76957695, Tick 4: 77207720, Tick 6: 77707770, Tick 7: 77957795, and Tick 8: 78207820.

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