Page 148 - NUMINO Challenge_M1

Problem solving

1 If a clock stops for 10 minutes at every hour, it reads 10 minutes slower at every

hour. So after 1 hour, it will read 10 minutes before the hour. After 2 hours, it will
read 20 minutes before the next hour. After 3 hours, it will read 30 minutes before
the next hour. The clock will read 3:30 at 4:00.

2 If Mina must get to school by 9, she must leave the house at 8:40. Mina’s living

room clock is set 5 minutes slow, so her clock reads 8:35 when the actual time is
8:40.

She must leave when her clock shows 8:35.

Creative Thinking

The clockwork toys walk in the same intervals, so the distance can be
compared by counting their steps.
Toy A walked 7 steps.
Toy B walked 7 steps.
Toy C walked 8 steps.

The toy that went the furthest is toy C.

In order to draw a line that is 4 cm, it must pass through 4 grid lengths.
Connect a path from point A to point B by only passing through 4 grid lengths.
AAA

B BB
AAA

B BB
A is the sum of the weights of B, C, and D, and it is the heaviest.
B is the sum of the weights of C and D, and it is the second heaviest.
D is twice the weight of C, and it is the third heaviest.

The lightest block is C.

11Answer Key