Understanding expressions, brackets, terms & properties
An arithmetic expression is a mathematical phrase that combines numbers with operations. Think of it as a compact way to describe a calculation.
13 + 2 = 15
20 − 4 = 16
12 × 5 = 60
18 ÷ 3 = 6
Every expression has a value — the number it evaluates to. The = sign shows the relationship between an expression and its value.
Mallika spends ₹25 every day for lunch from Monday to Friday.
Expression: 5 × 25 = 125
So Mallika spends ₹125 on lunch in a week.
We can compare expressions using >, <, and = by finding their values first.
Raja has 1023 + 125 marbles. Joy has 1022 + 128 marbles. Who has more?
Raja: 1023 + 125 = 1148
Joy: 1022 + 128 = 1150
Joy has 2 more marbles! So: 1023 + 125 < 1022 + 128
Compare: 113 − 25 vs 112 − 24
113 − 25 = 88
112 − 24 = 88
They are equal! So: 113 − 25 = 112 − 24
(a) 13 + 4 = + 6
(b) 22 + = 6 × 5
(c) 8 × = 64 ÷ 2
(d) 34 − = 25
67 − 19, 67 − 20, 35 + 25, 5 × 11, 120 ÷ 3
Values: 48, 47, 60, 55, 40
When an expression has more than one operation, things can get confusing — just like ambiguity in language!
Expression: 30 + 5 × 4
Who is right? Mallesh is correct! By convention, multiplication is done before addition.
Rule: Always evaluate expressions inside brackets first!
Irfan buys biscuits for ₹15 and toor dal for ₹56. He pays ₹100.
Correct: Change = 100 − (15 + 56) = 100 − 71 = ₹29
Wrong way: 100 − 15 + 56 = 85 + 56 = 141 ✘ (Absurd! More than he paid!)
Terms are the parts of an expression separated by the + sign.
Subtracting is the same as adding the inverse:
83 − 14 = 83 + (−14)
So the terms of 83 − 14 are: 83 and −14
−18 − 3 = (−18) + (−3)
Terms: −18 and −3
6 × 5 + 3
Terms: 6×5 and 3
6×5 is a single term!
Click "Reveal" to see the terms for each expression:
| Expression | Terms | |
|---|---|---|
| 13 − 2 + 6 | 13, −2, 6 | |
| 5 + 6×3 | 5, 6×3 | |
| 4 + 15 − 9 | 4, 15, −9 | |
| 23 − 2×4 + 16 | 23, −2×4, 16 | |
| 28 + 19 − 8 | 28, 19, −8 |
Swapping terms doesn't change the sum.
A drone goes 6 m up and then 4 m down.
Expression: 6 + (−4) = 2
Swap the terms: (−4) + 6 = 2
Same result! ✔
Grouping terms differently doesn't change the sum.
Evaluate (−7) + 10 + (−11) in different ways:
Way 1: [(−7) + 10] + (−11) = 3 + (−11) = −8
Way 2: (−7) + [10 + (−11)] = (−7) + (−1) = −8
Way 3: [(−7) + (−11)] + 10 = (−18) + 10 = −8
All give −8!
When an expression has multiplication, evaluate each term first, then add.
Terms: 30 and 5×4
Step 1: Evaluate 5 × 4 = 20
Step 2: Add: 30 + 20 = 50
A family orders 4 dosas at ₹23 each and gives a ₹5 tip.
Expression: 4 × 23 + 5 = 92 + 5 = ₹97
33 students play "Fire in the Mountain, Run Run Run!" They form groups of 5.
Expression: 6 × 5 + 3 = 30 + 3 = 33
6 complete groups with 3 students left over.
Raghu has 4 packets. His mother gives half of 100 more.
Expression: 4 + 100 ÷ 2 = 4 + 50 = 54 packets
Kannan pays ₹432 using notes and coins:
Expression: 4 × 100 + 1 × 20 + 1 × 10 + 2 × 1
= 400 + 20 + 10 + 2 = ₹432
Which grid matches 5 × 2 + 3?
We need a grid with 5 rows of 2, plus 3 extra = 13 cells
(a) 28 − 7 + 8 =
(b) 39 − 2×6 + 11 =
(c) 40 − 10 + 10 + 10 =
(d) 48 − 10×2 + 16÷2 =
(e) 6×3 − 4×8÷5 =
(a) 89 + 21 − 10
(b) 5 × 12 − 6
(c) 4 × 9 + 2 × 6
(a) A princess has 5 chests with 20 gold coins each, plus 13 loose coins. How many coins total?
Answer:
(b) A metro ticket costs ₹35. A family of 4 buys tickets but gets ₹10 discount. Total cost?
Answer:
(c) A window is at 12 m height. A ladder reaches 3 m above the window. Ladder length?
Answer: m
100 − (15 + 56)
= 100 − 15 − 56
= 29
500 − (250 − 100)
= 500 − 250 + 100 (the − flipped to +!)
= 350
NOT 500 − 250 − 100 = 150 ✘
28 + (35 − 10)
= 28 + 35 − 10 (signs stay the same!)
= 53
How does changing one term affect the value?
Answer:
Answer:
Answer:
(a) 38 − (−7) = 38 + =
(b) 17 + (−3) = 17 − =
(c) (−22) + 18 = 18 − =
(a) 13 − (6 + 3) =
(b) 13 − (6 − 3) =
(c) 13 + (6 + 3) =
(d) 13 + (6 − 3) =
(e) −(18 + 5) =
(f) −(18 − 5) =
(a) 43 − (12 + 9) vs 43 − 12 − 9 →
(b) 43 − (12 − 9) vs 43 − 12 − 9 →
(a) 16 − 4 + 2 = 10 → Write with brackets:
(b) 3 + 2 × 4 = 20 →
Try all combinations: 2+3+5, 2+3−5, 2−3+5, 2−3−5, etc.
Lhamo and Norbu each order a meal costing ₹43 for food + ₹24 for drink.
Expression: 2 × (43 + 24) = 2 × 67 = 134
OR: 2 × 43 + 2 × 24 = 86 + 48 = 134
Both ways give the same answer!
4 rows of soldiers + 3 rows of soldiers, each row has 5 soldiers.
4 × 5 + 3 × 5 = (4 + 3) × 5 = 7 × 5 = 35
Given that 53 × 18 = 954, find 63 × 18.
63 × 18 = (53 + 10) × 18 = 53×18 + 10×18 = 954 + 180 = 1134
Calculate 97 × 25 mentally:
97 × 25 = (100 − 3) × 25 = 100×25 − 3×25 = 2500 − 75 = 2425
(a) 102 × 7 =
(b) 98 × 12 =
(c) 999 × 4 =
(a) 3 × (5 + 2) =
(b) 7 × (8 − 3) =
(c) (10 + 4) × 6 =
(d) (20 − 3) × 5 =
(e) 6 × 12 + 6 × 8 = 6 ×
(f) 5 × 17 − 5 × 7 = 5 ×
(g) 101 × 13 =
(h) 99 × 15 =
(i) 48 × 9 =
(j) 52 × 11 =
(k) 4 × 63 + 4 × 37 =
(l) 7 × 84 − 7 × 34 =
(m) 997 × 5 =
(n) 1005 × 8 =
(o) 12 × 45 + 12 × 55 =
(p) 25 × 88 =
(a) 3×(4+5) vs 3×4+5 →
(b) 8×(7−2) vs 8×7−2 →
(c) 5×9+5×1 vs 5×(9+1) →
(d) 6×(10−3) vs 6×10−3 →
Answer:
A grid with 3 rows of 4 and 3 rows of 6:
Way 1: 3×4 + 3×6 = 12 + 18 = 30
Way 2: 3×(4+6) = 3×10 = 30
(a) A vendor has 5 baskets with 24 mangoes each, and gives away 18 mangoes. How many left?
Answer:
(b) Binu saves ₹15 daily. After 10 days, he spends ₹50. How much does he have?
Answer:
(c) A snail climbs 3 m up each day and slides 1 m down at night. After 5 days, how high is it?
Answer: m
(a) "I had 20 chocolates, gave 5 to each of 3 friends."
Expression:
(b) "4 packets of 6 pencils plus 2 loose pencils."
Expression:
Way 1: Group pairs: (1−2)+(3−4)+(5−6)+(7−8)+(9−10) = (−1)+(−1)+(−1)+(−1)+(−1) = −5
Way 2: Group differently: 1+(−2+3)+(−4+5)+(−6+7)+(−8+9)−10 = 1+1+1+1+1−10 = −5
Way 3: Positives: 1+3+5+7+9 = 25. Negatives: 2+4+6+8+10 = 30. Total: 25−30 = −5
(a) 28+32 vs 28+33 →
(b) 45−19 vs 45−20 →
(c) 7×8 vs 7×6+7×2 →
(d) 3×(5+2) vs 3×5+2 →
(e) 100−(30+20) vs 100−30+20 →
(f) 50−(25−10) vs 50−25−10 →
(g) 9×(8+3) vs 9×8+9×3 →
(h) 12×5−4 vs 12×(5−4) →
A: 8×6+8×4 • B: 8×(6+4) • C: 8×10 • D: 80 • E: 8×6+4
Put your expression skills to the ultimate test!
Using exactly three 3's and any operations (+, −, ×, ÷, brackets), make as many different values as possible.
Example: 3 + 3 + 3 = 9, 3 × 3 + 3 = 12, 3 × 3 × 3 = 27, 3 × 3 − 3 = 6, (3 + 3) × 3 = 18
Using exactly four 4's and any operations, try to make every number from 1 to 20.
Using digits 1, 2, 3, 4, 5 exactly once each with +, −, try to get every value from −10 to +10.
Using digits 0, 1, 2, 3, 4, 5, 6, 7, 8, 9 exactly once each, make an expression that equals 100.
Four full question paper sets covering all topics of Chapter 2. Click any set to expand it. Use "Show Answer" on each question or "Show All Answers" at the bottom of each set.