## 速算題 （一） <span>1. $35 \times 16 =$<!-- .element: class="fragment" data-fragment-index="1" --></span> <span>2. $28 \times 25 =$<!-- .element: class="fragment" data-fragment-index="2" --></span> <span>3. $375 \times 16 =$<!-- .element: class="fragment" data-fragment-index="3" --></span> <span>4. $24 \times 75 =$<!-- .element: class="fragment" data-fragment-index="4" --></span> <span>5. $52 \times 175 =$<!-- .element: class="fragment" data-fragment-index="5" --></span> [Online StopWatch](https://www.online-stopwatch.com/full-screen-stopwatch/) --- ## 速算題 （一）︰答案 <span>1. $35 \times 16 =$<!-- .element: class="fragment" data-fragment-index="1" --></span> <span> $560$<!-- .element: class="fragment" data-fragment-index="2" --></span> <span>2. $28 \times 25 =$<!-- .element: class="fragment" data-fragment-index="3" --></span> <span>$700$<!-- .element: class="fragment" data-fragment-index="4" --></span> <span>3. $375 \times 16 =$<!-- .element: class="fragment" data-fragment-index="5" --></span> <span>$6000$<!-- .element: class="fragment" data-fragment-index="6" --></span> <span>4. $24 \times 75 =$<!-- .element: class="fragment" data-fragment-index="7" --></span> <span>$1800$<!-- .element: class="fragment" data-fragment-index="8" --></span> <span>5. $52 \times 175 =$<!-- .element: class="fragment" data-fragment-index="9" --></span> <span>$9100$<!-- .element: class="fragment" data-fragment-index="10" --></span> --- ## 速算題 （一）︰解答 1. $35 \times 16$ = $5 \times 7 \times 4 \times 4$ = $7 \times 4 \times 5 \times 4$ = $28 \times 20$ = $560$ --- ### 速算題 （一）︰解答 2. $28 \times 25$ = $7 \times 4 \times 25$ = $7 \times 100$ = $700$ --- ## 速算題 （一）︰解答 3. $375 \times 16$ = $125 \times 3 \times 25$ = $7 \times 100$ = $700$ --- ## 速算題 （一）︰解答 4. $24 \times 75$ = $6 \times 4 \times 25 \times 3$ = $6 \times 3 \times 25 \times 4$ = $1800$ --- ## 速算題 （一）︰解答 5. $52 \times 175$ = $13 \times 4 \times 25 \times 7$ = $13 \times 7 \times 25 \times 4$ = $9100$