 𝐍𝐮𝐦𝐛𝐞𝐫𝐬 𝐚𝐧𝐝 𝐀𝐫𝐢𝐭𝐡𝐦𝐞𝐭𝐢𝐜 𝐎𝐩𝐞𝐫𝐚𝐭𝐢𝐨𝐧𝐬 
Countdown Mathematics Class 4
Third Edition
𝐂𝐡𝐚𝐩𝐭𝐞𝐫 # 𝟏
𝐖𝐨𝐫𝐝 𝐏𝐫𝐨𝐛𝐥𝐞𝐦𝐬

𝐍𝐨𝐭𝐞𝐬 𝐁𝐲: Adil Aslam 𝐒𝐮𝐛𝐣𝐞𝐜𝐭: Mathematics Class 4
1 | P a g e 𝐌𝐲 𝐄𝐦𝐚𝐢𝐥 𝐀𝐝𝐝𝐫𝐞𝐬𝐬: 𝐚𝐝𝐢𝐥𝐚𝐬𝐥𝐚𝐦𝟓𝟗𝟓𝟗@𝐠𝐦𝐚𝐢𝐥. 𝐜𝐨𝐦
𝐖𝐨𝐫𝐝 𝐏𝐫𝐨𝐛𝐥𝐞𝐦𝐬
𝐁𝐨𝐨𝐤 𝐏𝐚𝐠𝐞 # 𝟏𝟔
𝐍𝐨𝐭𝐞:
𝐒𝐨𝐥𝐯𝐞 𝐚𝐥𝐥 𝐪𝐮𝐞𝐬𝐭𝐢𝐨𝐧𝐬 𝐨𝐧 𝐲𝐨𝐮𝐫 𝐧𝐨𝐭𝐞 𝐛𝐨𝐨𝐤.
𝐏𝐥𝐞𝐚𝐬𝐞 𝐝𝐨 𝐚𝐥𝐥 𝐰𝐨𝐫𝐤 𝐧𝐞𝐚𝐭 𝐚𝐧𝐝 𝐜𝐥𝐞𝐚𝐧.
𝐒𝐨𝐥𝐯𝐞 𝐭𝐡𝐞 𝐩𝐫𝐨𝐛𝐥𝐞𝐦𝐬, 𝐰𝐫𝐢𝐭𝐢𝐧𝐠 𝐜𝐨𝐦𝐩𝐥𝐞𝐭𝐞 𝐬𝐭𝐚𝐭𝐞𝐦𝐞𝐧𝐭𝐬.
𝟏. 𝐀 𝐥𝐞𝐚𝐤𝐢𝐧𝐠 𝐭𝐚𝐩 𝐰𝐚𝐬𝐭𝐞𝐬 𝟑𝟕𝟓𝟎 𝒎𝒍 𝐨𝐟 𝐰𝐚𝐭𝐞𝐫 𝐢𝐧 𝟏 𝐡𝐨𝐮𝐫. 𝐇𝐨𝐰 𝐦𝐮𝐜𝐡 𝐰𝐚𝐭𝐞𝐫 𝐰𝐢𝐥𝐥 𝐛𝐞
𝐰𝐚𝐬𝐭𝐞𝐝 𝐢𝐧 𝐚 𝐝𝐚𝐲?
𝐒𝐨𝐥𝐮𝐭𝐢𝐨𝐧:
Water wasted in 1 hour = 3750 𝑚𝑙
We know that one day = 24 hours
Water wasted in 24 hours = 3750 × 24
Thus water wasted in 1 day = 90 000 𝑚𝑙
𝟐. 𝐑𝐞𝐡𝐚𝐧 𝐟𝐨𝐮𝐧𝐝 𝐨𝐮𝐭 𝐭𝐡𝐚𝐭 𝐡𝐞 𝐜𝐚𝐧 𝐬𝐚𝐯𝐞 𝟒𝟕𝟐𝟔 𝐦𝐥 𝐨𝐟 𝐰𝐚𝐭𝐞𝐫 𝐞𝐯𝐞𝐫𝐲 𝐝𝐚𝐲 𝐛𝐲 𝐧𝐨𝐭
𝐥𝐞𝐚𝐯𝐢𝐧𝐠 𝐭𝐡𝐞 𝐭𝐚𝐩 𝐨𝐩𝐞𝐧 𝐜𝐨𝐧𝐭𝐢𝐧𝐮𝐨𝐮𝐬𝐥𝐲, 𝐝𝐮𝐫𝐢𝐧𝐠 𝐡𝐢𝐬 𝐛𝐚𝐭𝐡. 𝐇𝐨𝐰 𝐦𝐮𝐜𝐡 𝐰𝐚𝐭𝐞𝐫
𝐜𝐚𝐧 𝐛𝐞 𝐬𝐚𝐯𝐞𝐝 𝐢𝐧 𝟐𝟓 𝐝𝐚𝐲𝐬 𝐢𝐧 𝐭𝐡𝐢𝐬 𝐦𝐚𝐧𝐧𝐞𝐫?
3 7 5 0
× 2 4
1 5 0 0 0
7 5 0 0
9 0 0 0 0
×



𝐍𝐨𝐭𝐞𝐬 𝐁𝐲: Adil Aslam 𝐒𝐮𝐛𝐣𝐞𝐜𝐭: Mathematics Class 4
2 | P a g e 𝐌𝐲 𝐄𝐦𝐚𝐢𝐥 𝐀𝐝𝐝𝐫𝐞𝐬𝐬: 𝐚𝐝𝐢𝐥𝐚𝐬𝐥𝐚𝐦𝟓𝟗𝟓𝟗@𝐠𝐦𝐚𝐢𝐥. 𝐜𝐨𝐦
𝐒𝐨𝐥𝐮𝐭𝐢𝐨𝐧:
Rehan save water 1 day = 4726 𝑚𝑙
Rehan save water in 25 days = 4726 × 25
Thus Rehan save water in 25 days = 118 150 𝑚𝑙
𝟑. 𝐓𝐡𝐞𝐫𝐞 𝐚𝐫𝐞 𝟏𝟒𝟒𝟎 𝐦𝐢𝐧𝐮𝐭𝐞𝐬 𝐢𝐧 𝐚 𝐝𝐚𝐲. 𝐇𝐨𝐰 𝐦𝐚𝐧𝐲 𝐦𝐢𝐧𝐮𝐭𝐞𝐬 𝐚𝐫𝐞 𝐭𝐡𝐞𝐫𝐞 𝐢𝐧 𝟖 𝐰𝐞𝐞𝐤𝐬?
𝐒𝐨𝐥𝐮𝐭𝐢𝐨𝐧:
Minutes in day = 1440
We know that 8 week = 7 × 8 = 56 days
Minutes in 56 days = 1440 × 56
Thus minutes in 8 weeks = 80 640
4 7 2 6
× 2 5
2 3 6 3 0
9 4 5 2
1 1 8 1 5 0
×


1 4 4 0
× 5 6
8 6 4 0
7 2 0 0
8 0 6 4 0
×

𝐍𝐨𝐭𝐞𝐬 𝐁𝐲: Adil Aslam 𝐒𝐮𝐛𝐣𝐞𝐜𝐭: Mathematics Class 4
3 | P a g e 𝐌𝐲 𝐄𝐦𝐚𝐢𝐥 𝐀𝐝𝐝𝐫𝐞𝐬𝐬: 𝐚𝐝𝐢𝐥𝐚𝐬𝐥𝐚𝐦𝟓𝟗𝟓𝟗@𝐠𝐦𝐚𝐢𝐥. 𝐜𝐨𝐦
𝟒. 𝐓𝐡𝐢𝐫𝐭𝐲 𝐜𝐡𝐢𝐥𝐝𝐫𝐞𝐧 𝐦𝐚𝐝𝐞 𝟓𝟐𝟖𝟎 𝐩𝐚𝐩𝐞𝐫 𝐛𝐚𝐠𝐬. 𝐇𝐨𝐰 𝐦𝐚𝐧𝐲 𝐝𝐢𝐝 𝐞𝐚𝐜𝐡 𝐜𝐡𝐢𝐥𝐝 𝐦𝐚𝐤𝐞?
𝐒𝐨𝐥𝐮𝐭𝐢𝐨𝐧:
30 children made paper bags = 5280
Each child make bags = 5280 ÷ 30
Thus each child make bags = 176
𝟓. 𝐇𝐨𝐰 𝐦𝐚𝐧𝐲 𝐩𝐢𝐞𝐜𝐞𝐬 𝐨𝐟 𝐜𝐥𝐨𝐭𝐡 𝐜𝐚𝐧 𝐛𝐞 𝐜𝐮𝐭 𝐟𝐫𝐨𝐦 𝐚 𝟓 𝒎 𝐥𝐞𝐧𝐠𝐭𝐡 𝐨𝐟 𝐜𝐥𝐨𝐭𝐡, 𝐢𝐟 𝐞𝐚𝐜𝐡
𝐩𝐢𝐞𝐜𝐞 𝐢𝐬 𝟓𝟎 𝒄𝒎 𝐥𝐨𝐧𝐠?
𝐒𝐨𝐥𝐮𝐭𝐢𝐨𝐧:
Total length of cloth = 5 𝑚 = 5 × 100 = 500 𝑐𝑚
Length of each piece = 50 𝑐𝑚
How many pieces can be cut out = 500 ÷ 50
Thus pieces can be cut out = 10
3 0 5 2 8 0
− 3 0
2 2 8
− 2 1 0
1 8 0
− 1 8 0
1 7 6
5 0 5 0 0
− 5 0

1 0


𝐍𝐨𝐭𝐞𝐬 𝐁𝐲: Adil Aslam 𝐒𝐮𝐛𝐣𝐞𝐜𝐭: Mathematics Class 4
4 | P a g e 𝐌𝐲 𝐄𝐦𝐚𝐢𝐥 𝐀𝐝𝐝𝐫𝐞𝐬𝐬: 𝐚𝐝𝐢𝐥𝐚𝐬𝐥𝐚𝐦𝟓𝟗𝟓𝟗@𝐠𝐦𝐚𝐢𝐥. 𝐜𝐨𝐦
𝟔. 𝐅𝐫𝐨𝐦 𝐬𝐞𝐫𝐯𝐚𝐥 𝐨𝐫𝐜𝐡𝐚𝐫𝐝𝐬, 𝐝𝐞𝐥𝐢𝐜𝐢𝐨𝐮𝐬 𝐚𝐩𝐩𝐥𝐞𝐬 𝐚𝐫𝐞 𝐩𝐚𝐜𝐤𝐞𝐝 𝐢𝐧 𝐛𝐨𝐱𝐞𝐬 𝐨𝐟 𝟕𝟐 𝐞𝐚𝐜𝐡.
𝐇𝐨𝐰 𝐦𝐚𝐧𝐲 𝐛𝐨𝐱𝐞𝐬 𝐰𝐢𝐥𝐥 𝐛𝐞 𝐫𝐞𝐪𝐮𝐢𝐫𝐞𝐝 𝐟𝐨𝐫 𝟗𝟑𝟔 𝐚𝐩𝐩𝐥𝐞𝐬?
𝐒𝐨𝐥𝐮𝐭𝐢𝐨𝐧:
Apples are packed in 1 box = 72
Total number of apples = 936
How many boxes will be required = 936 ÷ 72
Thus the number of boxes will be required = 13
𝟕. 𝐅𝐢𝐯𝐞 𝐝𝐨𝐜𝐭𝐨𝐫𝐬 𝐭𝐫𝐚𝐯𝐞𝐥 𝐟𝐫𝐨𝐦 𝐊𝐚𝐫𝐚𝐜𝐡𝐢 𝐭𝐨 𝐋𝐚𝐡𝐨𝐫𝐞 𝐭𝐨 𝐚𝐭𝐭𝐞𝐧𝐝 𝐚 𝐜𝐨𝐧𝐟𝐞𝐫𝐞𝐧𝐜𝐞. 𝐓𝐡𝐞
𝐭𝐨𝐭𝐚𝐥 𝐛𝐢𝐥𝐥 𝐟𝐨𝐫 𝐭𝐡𝐞𝐢𝐫 𝐭𝐫𝐚𝐢𝐧 𝐭𝐢𝐜𝐤𝐞𝐭𝐬 𝐢𝐬 𝐑𝐬 𝟗𝟔𝟕𝟓. 𝐇𝐨𝐰 𝐦𝐮𝐜𝐡 𝐝𝐨𝐞𝐬 𝐞𝐚𝐜𝐡 𝐝𝐨𝐜𝐭𝐨𝐫
𝐩𝐚𝐲?
𝐒𝐨𝐥𝐮𝐭𝐢𝐨𝐧:
Total number of doctors = 5
Total bill for their train tickets = Rs 9675
How much each doctor pay = 9675 ÷ 5
7 2 9 3 6
− 7 2
2 1 6
− 2 1 6

1 3
5 9 6 7 5
− 5
4 6
− 4 5
1 7
− 1 5
2 5
− 2 5

1 9 3 5
Thus each doctor pay = Rs 1935

𝐍𝐨𝐭𝐞𝐬 𝐁𝐲: Adil Aslam 𝐒𝐮𝐛𝐣𝐞𝐜𝐭: Mathematics Class 4
5 | P a g e 𝐌𝐲 𝐄𝐦𝐚𝐢𝐥 𝐀𝐝𝐝𝐫𝐞𝐬𝐬: 𝐚𝐝𝐢𝐥𝐚𝐬𝐥𝐚𝐦𝟓𝟗𝟓𝟗@𝐠𝐦𝐚𝐢𝐥. 𝐜𝐨𝐦
𝟖. 𝐇𝐨𝐰 𝐦𝐚𝐧𝐲 𝐡𝐨𝐮𝐫𝐬 𝐚𝐫𝐞 𝐭𝐡𝐞𝐫𝐞 𝐢𝐧 𝟐𝟕𝟎𝟎 𝐦𝐢𝐧𝐮𝐭𝐞𝐬?
𝐒𝐨𝐥𝐮𝐭𝐢𝐨𝐧:
Total number of minutes = 2700
We know 1 hour = 60 minutes
Number of hours = 2700 ÷ 60
Thus number of hours = 45
𝟗. 𝐅𝐨𝐮𝐫 𝐟𝐫𝐢𝐞𝐧𝐝𝐬 𝐬𝐡𝐚𝐫𝐞 𝐚 𝐟𝐥𝐚𝐭. 𝐓𝐡𝐞𝐢𝐫 𝐭𝐨𝐭𝐚𝐥 𝐞𝐱𝐩𝐞𝐧𝐬𝐞𝐬 𝐟𝐨𝐫 𝐉𝐚𝐧𝐮𝐚𝐫𝐲 𝐚𝐫𝐞 𝐑𝐬 𝟗𝟐𝟓𝟔.
𝐇𝐨𝐰 𝐦𝐮𝐜𝐡 𝐦𝐨𝐧𝐞𝐲 𝐦𝐮𝐬𝐭 𝐞𝐚𝐜𝐡 𝐟𝐫𝐢𝐞𝐧𝐝 𝐜𝐨𝐧𝐭𝐫𝐢𝐛𝐮𝐭𝐞?
𝐒𝐨𝐥𝐮𝐭𝐢𝐨𝐧:
Total number of friends = 4
Their total expenses = Rs 9256
Each friend contribute money = 9256 ÷ 4
6 0 2 7 0 0
− 2 4 0
3 0 0
− 3 0 0
4 5

4 9 2 5 6
− 8
1 2
− 1 2
5
− 4
1 6
− 1 6

2 3 14
Thus each contribute = Rs 2314