Questions

3 Marks Question

Take a timed test

23 questions · self-marked practice — reveal the answer and mark yourself.

Question 13 Marks
Can there be a number less than 0? Can you think of any way to have less than 0 of something?
Answer
Negative Numbers: Less than zero.
Yes, there can be numbers less than 0. These numbers are called negative numbers.
[While it might seem impossible to have less than nothing, but negative numbers are used in many real-world situations.]
Image
View full question & answer
Question 23 Marks
Can you explain each of Brahmagupta’s rules in terms of Bela’s buildings of fun, or in terms of a number line?
Answer
self
View full question & answer
Question 33 Marks
Here are six integer cards: (+1), (+7), (+18), (-5), (-2), (-9).
You can pick any of these and make an expression using addition(s) and subtraction(s).
Here is an expression: (+18) + (+1) – (+7) – (-2) which gives a value (+14).
Now, pick cards and make an expression such that its value is closer to (-30).
Answer
Let’s try to create an expression that gets as close to (-30) as possible using the given cards: (+1, +7, +18, -5, -2, -9).
One possible expression is: (-9) + (-5) + (-2) + (-18) + (+1)
Let’s calculate the value step by step:
1. (-9) + (-5) = -14
2. -14 + (-2) = -16
3. -16 + (-18) = -34
4. -34 + (+1) = -33
Hence, the value of this expression is (-33), which is quite close to (-30).
View full question & answer
Question 43 Marks
Complete the sequence:
______, ______, 12, 6, 1, (-3), (-6), ______, ______, ______
Answer
The numbers to the right of 12 are decreasing as per the following rule:
12 to 6 = -6
6 to 1 = -5
1 to -3 = -4
-3 to -6 = -3
So, further, they should decrease as follows:
-6 – 2 = -8
-8 – 1 = -9
Now, the numbers to the left of 12 should each increase as follows:
12 + 7 = 19
19 + 8 = 27
27, 19, 12, 6, 1, (-3), (-6), -8, -9, -9
View full question & answer
Question 53 Marks
Complete the sequence:
3, 4, 2, 5, 1, 6, 0, 7, ______, ______, ______
Answer
Identify the Differences Between Consecutive Terms:
3 to 4: +1
4 to 2: -2
2 to 5: +3
5 to 1: -4
1 to 6: +5
6 to 0: -6
0 to 7: +7
So, now 7 – 8 = -1
-1 + 9 = 8
8 – 10 = -2
Therefore, the required numbers are -1, 8 and -2
3, 4, 2, 5, 1, 6, 0, 7, -1, 8, -2
View full question & answer
Question 63 Marks
Find the years below.
(a) From the present year, which year was it 150 years ago?
(b) From the present year, which year was it 2200 years ago?
(Hint Recall that there was no year 0.)
(c) What will be the year 320 years after 680 BCE?
Answer
(a) 1874
(b) 176 BCE
(c) 360 BCE
View full question & answer
Question 73 Marks
Solve these:
8 – 13(-8) – (13)(-13) – (-8)(-13) + (-8)
8 + (-13)(-8) – (-13)(13) - 813 – (-8)
Answer
8 – 13 = -5(-8) – (13) = -21(-13) – (-8) = -5(-13) + (-8) = -21
8 + (-13) = -5(-8) – (-13) = 5(13) - 8 = 513 – (-8) = 21
View full question & answer
Question 83 Marks
Write all the integers between the given pairs, in increasing order.
(a) 0 and -7
(b) -4 and 4
(c) -8 and -15
(d) -30 and -23
Answer
(a) -6, -5, -4, -3, -2, -1
(b) -3, -2, -1, 0, 1, 2, 3
(c) -14, -13, -12, -11, -10, -9
(d) -29, -28, -27, -26, -25, -24
View full question & answer
Question 93 Marks
Make a border integer square puzzle and challenge your classmates.
Answer
Here’s the puzzle:
Image
Border sum: 2
View full question & answer
Question 103 Marks
For the last grid above, find more than one way of filling the numbers to get the border sum -4.
Answer
There are multiple ways to fill the last grid with a border sum of -4, here are two examples:
Image
View full question & answer
Question 123 Marks
What is the lowest point with respect to sea level on land or on the ocean floor? What is its height? (This height should be negative).
Answer
The lowest point on land with respect to sea level is the shoreline of the Dead Sea, which is approximately 1,410 feet (430 metres) below sea level. In terms of height, we can write it as approximately -1,410 feet or -430 metres.
But the lowest point on the ocean floor is the Challenger Deep in the Mariana Trench, which is about 36,070 feet or 10,994 metres below sea level. In terms of height, we can write it as -36070 feet or -10994 metres.
View full question & answer
Question 133 Marks
Looking at the geographical cross-section fill in the respective heights:
Image
Answer
A = +1500 m
B = -500 m
C = +300 m
D = -1200 m
E = +1200 m
F = -200 m
G = +100 m
View full question & answer
Question 143 Marks
Suppose you start with 0 rupees in your bank account, and then you have debits of ₹1, 2, 4, 8, 16, 32, 64, and 128, and then a single credit of ₹ 256. What is your bank account balance now?
Answer
Consider ‘credits’ as positive numbers and ‘debits’ as negative numbers.
Total credits = +256
Total debits = (-1) + (-2) + (-4) + (-8) + (-16) + (-32) + (-64)+ (-128) =-255
Account balance = Total credits + Total debits = (+256) + (-255) = +1
Hence, the account balance is ₹ 1.
View full question & answer
Question 153 Marks
Suppose you start with 0 rupees in your bank account, and then you have credits of ₹ 30, ₹ 40, and ₹ 50, and debits of ₹ 40, ₹ 50, and ₹ 60. What is your bank account balance now?
Answer
Here, Credits = ₹ 30 + ₹ 40 + ₹ 50 = ₹ 120
and Debits = ₹ 40 + ₹ 50 + ₹ 60 = ₹ 150
∴ Balance = Credits – Debits
= ₹ 120 – ₹ 150
= – ₹30
Therefore, your bank account balance is – ₹ 30.
View full question & answer
Question 163 Marks
Try to subtract – 3 – (+ 5).
How many zero pairs will you have to put in? What is the result?
Answer
You have – 3 (3 negative tokens). Subtracting + 5 means you need to remove 5 positive tokens.
Add 5 zero pairs to introduce 5 positive tokens that can be removed.
Remove the 5 positive tokens.
After removing these, you are left with 3 original negative tokens and 5 additional negative tokens.
3 original negative tokens + 5 additional negative tokens
= 8 negative tokens
So, the result is – 8 and you needed to add 5 zero pairs to perform the subtraction.
– 3 – (+ 5) = – 8
View full question & answer
Question 173 Marks
If Floor A = -12, Floor D = -1 and Floor E = +1 in the building shown on the right as a line, find the numbers of Floors B, C, F, G and H.
Image
Answer
Floor B is 9 floors lower than Floor 0.
So, the number of Floor B is -9.
Floor C is 6 floors lower than Floor 0.
So, the number of Floor C is -6.
Floor F is 2 floors higher than Floor 0.
So, the number of Floor F is +2.
Floor G is 6 floors higher than Floor 0.
So, the number of Floor G is +6.
Floor H is 11 floors higher than Floor 0.
So, the number of Floor H is +11.
View full question & answer
Question 183 Marks
What do you press to go four floors up? What do you press to go three floors down?
Image
Answer
If you press the ‘+’ button once then you will go up one floor and if you press the ‘-‘ button once then you will go down 1 floor.
Hence to go four floors up you must press the ‘+’ button four times which we write as + + + + or +4.
Now to go three floors down you must press the button three times which we write as – – – or -3.
View full question & answer
Question 193 Marks
Number all the Floors in the Building of Fun.
Image
Answer
Let’s mark numbers on all the Floors in the Building of Fun.
Image
View full question & answer
Question 203 Marks
In the other exercises that you did above, did you notice that subtracting a negative number was the same as adding the corresponding positive number?
Answer
Subtracting a number is the same as adding it’s opposite. So subtracting a positive number is like adding a negative number – you move to the left on the number line. Subtracting a negative number is like adding a positive number – you move to the right on the number line.
For example: Subtract -2 – (-3)
Start at -2 and move 3 units to the right.
Image
So, -2 – (-3) = +1
View full question & answer
Question 213 Marks
Evaluate 15 – 5, 100 – 10, and 74 – 34 from this perspective.
Answer
(a) There are 15 pens in the shop. I take away 5 pens. How many pens are left in the shop?
Then 15 – 5 = 10
(b) There are loo books on the shelf. I take away 10 books. How many are left on the shelf?
Then 100 – 10 = 90
(c) There are 74 books on the shelf. I take away 34 books. How many are left on the shelf?
Then 74 – 34 = 40
View full question & answer
Question 223 Marks
Write the inverses of these numbers:
+4, -4, -3, 0, +2, -1
Answer
The additive inverse of +4 = -(+4) = -4.
The additive inverse of -4 = -(-4) = +4.
The additive inverse of -3 = -(-3) = +3.
The additive inverse of zero (0) is zero itself
The additive inverse of +2 = -(+2) = -2.
The additive inverse of -1 = -(-1) = +1.
View full question & answer
Question 233 Marks
Start from the Food Court and press +2 in the lift Where will you reach? _________
Answer
Here, Target floor = Starting floor + Movement
∴ The starting floor is +1 (Food Court) and the number of button presses is +2.
Therefore, floor = starting floor + movement
= (+1) + (+2)
= +3 (Book Store)
View full question & answer