SEAMO 2020 — Paper B — Grade 3–4

Evaluate $1\div(2\div3)\div(3\div4)\div(4\div5)\div(5\div6)$.

Find the number represented by the last figure.

How many dots are in Figure $8$?

Define $M\star N=4M-3N$. Find $x$ if $x\star1=17$.

$ABCD$ is a square of side $5\text{ cm}$. Points $B,C,E$ are collinear and $CE=a$. The shaded region $y$ is $5\text{ cm}^2$ larger than shaded region $x$. Find $a$.

A square has diagonal $12\text{ cm}$. Find its area.

A prime number has exactly two positive factors, $1$ and itself. Two primes sum to $34$. Find their smallest possible product.

Find $B$ in the circle number puzzle.

How many terms are in $4,10,16,22,28,\ldots,64$?

Marvin writes $1,2,3,4,5,6,7,\ldots$ on the board. What is the $177$th digit he writes?

How many digits are in $111111111\times111111111$?

Evaluate $1-2+3-4+5-6+7-\cdots-2018+2019$.

Nutcharat drives from Chiang Mai to Bangkok at $120\text{ km/h}$ and returns at $80\text{ km/h}$. Find her average speed for the entire trip.

Emma’s wallet is stolen. Adam says, “Ben stole it”; Ben says, “Not me”; Charles says, “It wasn’t me.” Only one person tells the truth. Who stole the wallet?

Find the largest four-digit common multiple of $5$ and $8$.

What is the first number in row $10$ of the array?

The signs $\gt $ and $\lt $ mean greater and less. Given $A=98765\times87654$ and $B=98756\times87663$, which is true?

A school rents boats for $48$ students. A small boat fits $3$ and costs $4$ dollars; a big boat fits $5$ and costs $6$ dollars. Find the minimum rental cost.

First, two more than half the apples in a basket are removed. Then two less than half the remaining apples are removed. Finally $20$ remain. How many were there initially?

How many squares are in the $4\times4$ grid?